I totally I agree with this!! I have been vegetarian for as long as I can remember, my parents wanted to raise us in a vegetarian way, now I am the only one of my siblings who does not eat meat. To me there's several reasons, the most important one being the meat industry here in Holland being totally awful, not only to the annimals, but also causing 10% of the CO2 production in Holland!!
(these are among other reasons)
How ever, I never bug anyone about their eating habits, I never tell any one I think my vision of the food production is superior to theirs, I never want any one to change the way they live/think, however, people seem to think that if they are having dinner with a vegetarian (mostly this happens at restaurants) they are in need to start arguing about wether or not being a vegetarian is a good idea... I usually don't feel like discussing this, to me it was well-thought decision, I should not have to defend myself to anyone whenever I have dinner... Usually people make me feel bad, this I hate, I don't do it to them, I don't get why they do it to me...
this has been really troubeling me for quite sometime now.... so that might be why I come of forcefully... is this the same way in America? We actually have quite a lot of vegetarians here, but this attitude has not changed over the last 10-15 years (before that time, I guess it ws my parents who had to endure it

)