Not so much: "We all want to go to and eat bosintang. You can go eat at MacDonald's by yourself." This comes across a bit more like an ousting, and I can see why it wouldn't go over too well.
What would you suggest in this situation, where everyone but 1 person wants to try something new and local/spicy/meaty and a lone person doesn't? I think saying those people shouldn't go eat that special thing they want isn't fair either. I would be incredibly frustrated by this situation. Sometimes I feel like it ends up always ending up with the least adventurous eater getting their way. And while I wouldn't be nasty about it, nor would I be OK with going to McDonald's to keep someone company rather than eating X thing I liked.
I'd be fine with something like, they come along to the restaurant but don't eat anything, but instead eat before or after, if that works at all. Not sure if it would in all cases, though.
Bear in mind that I'm approaching this question from Thipu's perspective. I'm taking into account that one person's "picky" might be another person's allergy, intolerance, or values-based restriction. I give people who have health or moral/religions restrictions a bit more leeway than people with vast quantities of gustatory preferences.
I think absolute "My way or the highway" attitudes are pretty off-putting whether they come from the majority or minority.
I think that if one member of the group has an absolute restriction, it's better for the group to be sensitive of it. Take, for instance, seafood restaurants. There are ones around here that literally have no fish-free options (beyond, perhaps, cole slaw. . . even the chips are fried in the same oil as the fish, which ). A person who cannot eat fish for one reason or another might not have anything to eat at all if everyone goes there.
If the group is only going to be in the vicinity of this restaurant once, of course they shouldn't all be expected to skip out on it. However, I think they should do the best to accommodate the other person as well as they could. Even offering a choice (say, "Would you prefer to split up and meet later, or do you want to sit with us while we eat and we'll help you find a place to get takeaway afterward?") would be preferable than telling them that they're out of luck. If, however, the group is going to be in the area for more than one meal, it would be gracious (no necessary
, but gracious) for someone to offer to accompany the person who cannot eat at the one restaurant for at least one meal elsewhere.