There are a hundred rational and emotional reasons someone becomes vegan. There are hundreds more defensive and irrational reasons vegans are hated. There are also many big businesses that depend on people dismissing vegans as 'extreme' and perpetuating the myth that it's an unhealthy lifestyle. I'll just go through a few of them briefly because I'm sure you all have the ability to do a Google search all on your own.
1) Environmental - I found it extremely odd that, outside of the vegan community, no one seems to know that animal agriculture is the largest contributor to greenhouse gas emissions, the majority of the destruction of the rainforest and most of the water and food resources in the world. You'd have to go months without showering to save the same amount of water used to make one hamburger. And don't even get me started on what all that animal waste has done to our waterways. I strongly recommend watching Cowspiracy or at least going to their fact check page here.
2) People - Going back to all the food used to feed animals for us to eat, we're basically letting poor people in this world starve so that we can feed the food of the rich people. We talk a lot about the one percenters, but eating meat is the ultimate eff off to poor people. "Sorry, we could give you food, but we need it to fatten up our cows." Not to mention all the antibacterial-resistance being bred on factory farms.
3) Animals - Of course, we're all told that animals we eat are unaware and don't feel pain. But that's scientifically disproven. Pigs are smarter than dogs. All farm animals are sentient - meaning they're capable of suffering and understanding that they're suffering. It just doesn't make sense to see some animals as our friends and others as our food. If you think your meat is roaming around on a hillside somewhere enjoying life until one day your friendly farmer humanely knocks them out and painlessly kills them, you need to do some research. "Farm" animals are basically emotionally and physically tortured their entire life. The same things that we would all revolt against if done to a dog are legally done to pigs, cows and chickens because anything that is considered 'standard practice' is legal and therefore not considered abuse. If you can't stand to watch an undercover video, you probably shouldn't be eating the product of it. And if you think the undercover videos are bad, research what 'standard practices' are, because they're not prosecutable and normally don't wind up in these videos. And vegetarianism is not the answer. Dairy cows are the most abused animals (in my opinion). They are kept pregnant most of their lives and cry for days for their calves which are taken away days after being born. Bottom line: The meat industry and dairy industry are linked, and eating cheese supports the veal and beef industries. There's also no such thing as humane meat or eggs. Just research what cage free actually means, and you won't be impressed.
The only real arguments people seem to have against veganism is 'I don't care', 'I don't want to change', 'vegans are idiot bullies' and 'don't tell me how to live my life - you made your choice, mine is to eat animals.'
If you don't care, I can't help you much. The earth is beginning to force us to care. If you have kids, I'm not sure how you could be okay with knowingly being a part of what is swiftly becoming an unstoppable spiral into our own destruction. International watchdogs have basically said global warming is no longer stoppable and we can only hope now to minimize the extent of it. The UN in 2010 told us nonvegan diets are destroying the earth and are unsustainable. I'm not sure if that message got to the people participating in the People's Climate March this September.
The I-don't-want-to-change-ers, I understand. But it's definitely not as hard as it seems. There's tons of great vegan food available. And with great substitutes such as Beyond Meat, Gardein and Field Roast out there, you can veganize most all of your favorite recipes. There's great vegan ice cream, candy, frozen meals, yogurts, breads, etc. around. Also, you can find a vegan recipe for anything online. One of my favorite sites is VegWeb.com. I went vegan overnight, but there's plenty of people that slowly incorporate vegan meals into their pre-vegan diet. Happy Cow is an app that can direct you to a vegan-friendly restaurants near your home or while you're on the road. Many fast food and fast casual restaurants have vegan options. It's always difficult to make changes, but when you see all that's at stake, it should be harder to do nothing.
Vegans are idiot bullies - these are my favorite kind of anti-vegans. I feel these guys are just a bit of information away from becoming vegan themselves. You can't be that passionately against something without it affecting you. They usually resort to name calling because they don't have any rational argument against it. They just lash out, hoping you'll go away and stop making them feel guilty about their 'choices'.
Which leads us to the choicers. But we're forgetting that the animals are not given choice in all this. If things were to be switched around - say an alien life or another animal makes its way to the top of the food chain and decide they like human meat and milk, I doubt you'd be so protective of their choices. Unless you'd be okay with humans being forcibly impregnated, imprisoned, tortured, then how is it okay for us to do it to animals who are also aware of what is going on?
Personal choice - yes, it is a personal choice. You can choose to lower your impact on the environment without having to change any laws. Voting with your dollars is the best way to have your voice heard. And the more that people are making changes based on being conscientious consumers, the more industry is taking note and making changes.
There's also all the biological and hypothetical reasons which I don't even really like to address - we have canines - so do lots of herbivores. You need protein from meat - no you don't (the animals you eat definitely didn't.) And calcium - many studies show that calcium from animals is way more harmful than calcium from leafy greens and, in fact, causes osteoporosis and many cancers. Dairy is a carcinogen. If I were stranded on a desert island - talk to me then; we are no longer animals hunting and gathering.
Veganism is just the next step in social evolution. At one point people who thought slavery was wrong were 'extreme'. Not all that long ago, women weren't allowed to vote. I understand we were all born into this and the facts are not advertised while the lies are. But we all readily hate the banks and Wall Street for their deceptions and accept Big Animal Ag's without a thought. Looking behind the curtain is our duty as citizens in this capitalist society. If we accept what those in power say or are too easily distracted to care, we may as well be living in a dictatorship. The whole evil-prospers-if-good-people-do-nothing's very paraphrased quote is the theme of this post. So, annoying? Probably. But if you were stuck in a cult where 95% of the people were blindly following and handing their earnings over to its charismatic leader with a good marketing team, while he slowly destroys everyone's home, you'd probably seem a little annoying to those you were trying to open the eyes of.