The idea here is that eating meat is normal, and you're weird if you don't.
The fact that most people engage in unethical behavior should be justification for yourself. I'm not judgmental about it; I understand it's culturally ingrained and no one has really thought about it at all. But that's not an ethical argument for doing it.
Try to think of a time in history when discrimination against members of other groups, whether by sexual orientation, gender, or race, may have been commonplace. Was it ok then? Is it ok that we continue the discrimination based on species?
People go to grocery stores and pick up neatly cling-film-wrapped packages of squiggly red playdough that turns brown on the stovetop; it's totally disconnected from the actual thing. Studies show that this small disconnect leads to huge implications on what people are interested in tolerating in terms of unethical behavior. Combine that with eating meat being the path of least resistance and the tacit approval of all those around you, and it's not that surprising.
We'll change that, don't worry.