Some pointless rationalization:
Suppose person X grew up, for whatever reason, a vegetarian. Person Y thinks vegetarianism is bunk, a completely ridiculous and pointless restriction, and tells person X to just try meat once. Person X says they just don't really like the idea of eating dead animals, but person Y insists that person X won't know what they're missing until they try it. For the sake of argument, assume person X is not even all militantly everyone-should-be-vegetarian, just the concept of eating meat is just kind of weird and unpleasant to them.
Think about whose side you're on in this debate, if you think one or both parties are being retarded in some way. Now replace "vegetarian" with "doesn't drink alcohol" and "eating dead animals" with "intentionally ingesting things to lower one's inhibitions/make one more social/etc.". Does this change your attitude? Why or why not?