There is a summary of veganism that follows the principle that we shouldn't take sentient things and change their lives for our own ends. There are several important bits and nuances but the overarching point is to not have a world view where you see anything and prioritize what you can get out of it, regardless of the suffering you cause. Sometimes you hear it summarized as "they arent here for us".
It is an interesting philosophical bit and it combines pretty standard modern morality with a pointed concept of not discriminating by species and instead trying to use the ability to suffer as when you decide if you should exploit something. In this paradigm the reasons not to rape or enslave people are the same as the reasons not to rape or enslave other animals.
This still has plenty of inconsistencies and weird bits, both theoretically and practically. Silly questions like eating braindead people stymie both sides until you get into the weeds about stuff like dignity. Would the theoretical cows in the hitchhikers guide that WANT to be eaten be ok to eat? Is it ok to have second hand animal products, especially if they are high quality and will prevent additional exploitation/consumption?
One of the most sticky conundrums I personally chew on is if this means we should actively try to prevent suffering, not just choose to personally try to avoid causing it. If the former, that means trying to make other people change their beliefs and behave in a way that is pretty objectively worse for them in society, which starts to edge toward causing suffering if you squint. It is easy to fall into trying to reason about which suffering is worse which is a terrible minefield where everybody loses. It's easy to SAY I value something no longer being tortured over my taste preference but is there a logical framework for that that can ever be objective and applied to harder problems? If it is only subjective then what makes it better than any other decision - people decide to eat pigs but not dogs every day but there is no more OR LESS reason behind that than the claim above. There might be answers but I haven't found them to be easy to pin down which is especially interesting because of how strongly I feel that not caring any hurting things is bad.
tl;dr being vegan sucks