Veganism is actually a pretty difficult philosophy to challenge for the average idiot, not that you have to understand any of that to be a vegan, a lot of people just do it because they like animals or whatever.
I'd wager most people would agree to the sentiment that suffering should be reduced wherever possible, however most people aren't vegan, so there's some disconnect there. It's totally plausible for the average American to never eat meat again, in some cases cheaper on their budget even (given you don't live in a food desert), so the real question is why doesn't the average person? I'd argue that people think of humans as "different" or above animals and that gives them some reasoning to justify it to themselves. But in reality humans are just another species of animal, there's nothing out there that says we're "special", that no other forms of life can reach the level we have. Another reason I think is that a lot of people also think of animals as "unfeeling", like robots, but biological life. I think this is a mistaken notion, there are many documented cases of animals displaying what appears to be empathy, not only within species, but across the lines of species. Additionally most people would feel pretty queasy about eating a dog, but are fine with bacon or pork products, even though pigs are technically more intelligent animals.
So ultimately, if you think suffering should be reduced wherever possible (within the realms of being able to live a healthy and comfortable life let's say), what are the reasons for remaining a carnist (eating meat)? I don't think there are any really, and you can feel free to debate me on this, but I don't think there's a consistent worldview that allows the average first world middle-class citizen to minimize suffering while eating meat. I personally don't even think suffering is reducible because merely continuing to live is in essence a selfish act. Rather I think patterns of co-operation and nonviolence are evolutionary advantages meant to give both me and my fellow humans a leg up. If the biggest threat towards my own existence is another human, then language empathy and communication are advanced ways to communicate a "cease fire" so to speak, as we both pose the biggest threat towards the other's existence. I do this not out of a wish to minimize risk for my neighbor, but as a way to minimize risk for myself, which plays into the "selfishness" I mentioned earlier. With most animals this doesn't really exist. I as a human cannot communicate this proverbial "cease fire" of sorts with a bear, as if a bear cannot interpret what I communicate, there's no guarantee of my own "selfish" gain. Therefore this argument for veganism holds no real value to me.
There are other reasons to consider veganism or limiting your consumption of meat that I think hold a little more value. I would be more swayed to veganism personally from a conservation standpoint because the meat industry is not only inefficient, it is also one of the largest causes of pollution on a global scale. Additionally at the rate we continue to consume meat, it seems completely unsustainable to keep going, we'll either have to figure out several effective work-arounds or perfect and create an industry for lab meat.
Food for thought.