I've been a pseudo vegetarian (just eat fish) for about 6 years. I don't have any problem with other people eating meat, it just doesn't sit right with me ( in my head).
The way I justify it is like this: Anything that I would willingly kill myself in order to get the meal, I will eat. Anything that I wouldn't willingly kill myself in order to get the meal, I pass up.
Someday I might slaughter a chicken and then start eating chicken again.
I have no problem whacking little fishees agains the side of the boat, so I eat fish.
Some people don't understand this pholosophy, but it works for me. To each his own
-P