Because sometimes it's worth the camaraderie to "take one for the team". Sometimes if you're the only one in a large group that actually dislikes something, you keep your trap shut.
It depends on the personalities of everyone involved, the strengths of their feelings on the matter, etc. There's a lot of variability involved.
I'll do something I fear will be boring or go to restaurant I don't love for my friends. But I won't take a 3D headache or eat at a restaurant that has nothing but stuff I'm allergic to, because headaches suck. (Turns out both my clauses converge on that "because".) At the risk of channeling $STEREOTYPICAL_MOM, are people who'd ask that of you really your friends?
Lack of sleep gives me headaches. Sometimes (but not always), 3D movies do too. They're always more fatiguing than 2D movies, at the very least.
> At the risk of channeling $STEREOTYPICAL_MOM, are people who'd ask that of you really your friends?
They don't know, because I don't tell them. Otherwise, they'd bend over backwards to accommodate me, which would make me more uncomfortable than the physical pain does.
You'd choose differently than I would, apparently. Having tried both approaches to dealing with the situation (with other groups of people), I've decided that I prefer this one. You can take your condescension and shove it up your ass; it serves no useful purpose here.
I just checked local Cinemark and most movies showing (including the Star Wars one) are available in non-3D. So it may be not the function of availability :)
3D can reduce the availability of 2D showings by 50%, so if there are half as many times when 2D is showing, then there will be customers that choose not to see the film because showtimes don't fit their schedule.
Source: Myself, a dad that only sees movies a couple times a month during a very limited time period when the babysitter is available