In my opinion it's quite simple. I eat what I would be willing to personally kill and butcher myself. I think trying to justify why 'A' and not 'B' to ourselves is somewhat unproductive. Two people watch a movie, one person likes it - the other dislikes it. Both can give their reasons for such, but neither is right or wrong.

Attempting to quantify subjective matters is arguably one of the big reasons so many of the social sciences are facing replication crises. There are so many factors in play that the quantifications, or justifications, we provide to explain social phenomena like this are not very meaningful even if we think they are! The most important thing is to be aware of the facts, so much as possible, but beyond that simply to take your opinion as what it is - a subjective view based on a complex series of mental interactions that even you are not fully privy to.