I think my biggest issue with 'meat' is when people disassociate it with the animal completely. I had a friend who couldn't eat whole fish, because she couldn't take looking at the face, but if it was fried in batter and served with chips as a fillet, no big deal. Missing out on fish cheeks, the softest and most tender part of the fish!
If you understand where you food comes from, that's fine to me. If you don't want to eat certain types of food for cultural reasons or because there's an emotional attachment (ie. dogs, cats) that's fine, I have a friend who's Buddhist, who loves pork and lamb but doesn't tuck into beef because of her Buddhism. I also have friends who won't eat lamb because they find the smell too overpowering (but all the more for me). But I also won't judge people who do eat things I may not be so comfortable with.
Having said that though, I'm certainly pleased if people are willing to be open minded. If you are happy to eat beef, why not try the tripe? Or the tongue? You know the animal won't kill you and it's from the same beast.
And I can also understand why some people would prefer not to have the brains, but be happy to have steak. The texture is very different, lamb brains at least are very soft, and usually a white and grey-ish colour, which is not naturally appealling to the eye. We're only human, being in the fortunate position we are in, we will be more drawn to eat the things that look good to us than not right?
People can also get put off stuff if they've had a bad experience with it. I once had lung and hated it, but once had lung and really liked it, different ways or preparing things right?
I've had my boyfriend try beef tendon and it's something he probably wouldn't have again as the jelly-ish texture weirded him out a bit, as it's a texture he doesn't really like (doesn't like soft tofu etc. either).
I personally think it's a bit too big of a blanket statement to say that if you eat one kind of meat, you eat all of it. I would certainly advocate that people do try to get a little adventurous, and for more food education in general, which is why I love shows like Anthony Bourdain's No Reservations or Andrew Zimmerman (I think?) show of weird and wacky food.
Personally though, I'm down for offal. Have had brains, lung, blood (black pudding is the best <3), intestines, stomach, trotters, tongue, sweet breads, tendons, cheek and who else knows what.
Insects are also, when properly done, actually really good for you. I think there was an article recently that discussed that we should plan to have more insect based diets because they're high in protein and very sustainable to farm. I've had fried crickets in Bangkok, so crunchy and salty. Although it's kind of weird when the legs scratch up against the roof of your mouth.
tl:dr : I've eaten lambs brain and loved it.