We're plenty sensitive. Our Fe sucks. Therefore we have trouble knowing what to do with what people think about us (criticism), but also, we have trouble sharing/expressing that. So we look less sensitive, not more. We can look insensitive because we really don't care about something you expect us to, too.
Like with any type, the healthier we are, the less sensitive we get. That varies a lot within any type.
I do this. Excuse the rant, but that sort of thing happens to me a lot. Hopefully at least OP finds it illuminating.
This is also inferior Fe. If you're being vague about things, kind of saying you want to see a movie but also implying you don't (or the other way around), there's obviously some emotional subtext an ISTP is "supposed" to pick up on. But with crap Fe, we don't know what! We just know that the words coming out of your mouth have nothing to do with what your real, honest answer is. But that usually when people communicate that way, they expect us to have understood the real answer as though they actually said it. (Somehow, magically, by reading their minds.)
This is really stressful and makes us try to avoid the whole problem by demanding you just say your exact, literal meaning. That way, your boyfriend doesn't take you all the way to the movie, just for you to finally let on that no, you didn't really want to come here in the first place, and what's wrong with him for making you come here? I have been blamed for "making" people do what they literally told me they wanted to do before, because I didn't pick up on some obscure clue that they didn't mean it. To me, this is just being lied to and then attacked.
An ITP that's experienced this enough can get oversensitive, and see it when it's not there. Sometimes people are straightforward, but we can't tell for sure. That might be what's going on if you're telling your ISTP the truth and he still keeps asking. He needs your whole thought process to be sure, because where you say he doesn't want to "figure it out himself," there may not be a way to do that. Either you tell him, or he takes wild guesses in the dark. That's how it is for me.
Being unclear to avoid hurting my feelings will always hurt my feelings more. If someone just doesn't want what I want, that's fine. Why would they be me? We'll find some other common ground. But if they go along with me anyway then when I find out, I've been: lied to, embarrassed (this whole time they knew something I didn't), patronized, tricked into burdening them, and dismissed (I asked what they wanted, and they ignored that request).
It's sensitivity, I guess. A specific learned sensitivity from years of having people make me guess, then be inexplicably mad at me when I didn't guess right. It's trying to avoid a problem but overcompensating.