""Not me! I'm not like that!" I haven't figured out a polite way to say, "Okay, then this thread is discussing the other 5,999,999,999 people in the world.""
I hate that, and I hate its cousin - "don't forget about this tiny subset!" Like, let's say someone is hosting Thanksgiving, so they post their menu on the board. I would be willing to bet a doughnut that someone will say "but what will the vegetarians/diabetics/etc. have to eat?" It's all I can do not to reply "I'm sure the OP knows her guests, and has planned the menu accordingly." Because if you're on an etiquette forum, I'd assume that you would want to accomodate your guests as well as you could - so if you DID have a guest or two who were vegetarian, you'd have, for example, a veggie lasagna and make sure most/all of the sides were meat-free.