I agree with this comparison and becoming vegan has made me more tolerant of the pro-life viewpoints (even though I still don't agree with it). Louis C.K. did a bit which explains it where he was making fun of people who whine about pro-lifers and where he said 'They think babies are being murdered! how else would you expect them to act?'. Its a brilliant line because it really shows how intolerant to opposing viewpoints mainstream society is.

Think about it this way, if you saw brutal injustices occurring everyday and you did nothing to stop it, what kind of person would that make you? Sure you could argue that vegans are wrong but put that aside for a moment and just think about the viewpoint of vegans. Obviously they think they are right, so should they not do everything in their power to correct what they see as murder and violence on sentient beings? Do you really think the paper-thin arguments that you provide in your post are sufficient for doubt when the possibly of being wrong means you condone mass murder? Its a pretty big question and one that require some thought and not a quick dismal. The same is true for abortion, the stakes are pretty fucking high if we are not 100% sure the terminating pregnancies is not actually killing a living, conscious person. It requires careful thought, study and reflection before you can say with conviction how other people should act. If you haven't gone through that kind of rigorous critique of your own beliefs, you best stay out of the discussion.