LogFAQs > #946721596

If someone has a visceral negative reaction to "I don't eat meat" or "I don't eat animal products," it's likely because they realize, at a subconscious level, that they know that not eating such things displays a superior willpower or morality. In short, they feel offended, as if the other person insulted them. Even if the vegan only commented on their own eating habits.

Compare this to when people say "I don't eat seafood" or "I don't eat broccoli." People don't get insulted by these statements. Because people don't attach morality or willpower to these statements.