Last BBQ I hosted couple of vegetarians came over so we gave them their own separate BBQ so the food wouldn't be contaminated, no complaints so far..... Yet they then moaned and whinged whenever meat was being cooked on the other one that the smell 'was offensive'. Er what?
Same goes for the people that moan about the free home brew I provide, if you don't like it then go buy your own!
It's perfectly understandable that a vegetarian might not wish to buy, prepare or cook meat.
If I went to the trouble of preparing you a meal, and you suddenly demanded something else, I'd get pretty indignant too, because of your total lack of manners.
the issue is, that some vegetarians have accepted an invite to come to a place where they know people are going to be sticking half a dead cow on top of some flames and cooking it, they know it's going to smell of cooked meat, they know people are going to be eating it
so they accept the invitation and then complain about it.
if you can't stand the smell of meat cooking, there are three things you can do about it:
1) not go
2) stand upwind of the BBQ so the smell blows away
3) get out of the kitchen / garden
4) grow a pair and man up - you aren't in kindergarten anymore, people aren't going to let you choose which biscuits everyone has at snack time because it's your turn to pick because you're a special little boy etc etc and other condescending things I haven't yet thought of aimed at people who unreasonably expect things of others.
with regards to eating, my wife is really quite fussy but it's only me that gets annoyed by it as she won't eat beef (taste and texture) and isn't keen on tomato (has got better since we married) and will now eat melted cheese - i love lasagne, ah well.
when we get invited to a friend's for food, I politely accept and mention that my wife isn't too keen on beef, lots of tomato and prefers mild spice and have found people to be fine with it, just like if I invite someone i'll ask if there is anything they don't / can't eat and plan accordingly.
I do have one friend who's eating habits are really quite narrow, so he doesn't accept dinner invites but suggests going to a pub for food instead.