The thing about nonconsensual mindreading/mindprobing/whatever is that the victim has no way of knowing whether the perpetrator "just" looked for one specific piece of surface knowledge or not. Maybe the SHIELD psychic just went in, Google "House of M" in my brain, and came out...or maybe she didn't. Maybe she went rifling through all my thoughts, from my secret identity to all those little things about myself I've never told anyone. Maybe she left a psychic suggestion behind. Maybe she altered my perceptions in some way. Maybe she made me walk out into the hallway and murder someone. I can't tell. Crossbones doesn't know his memory has been altered; if Xavier had decided to do so as well, would Crossbones have been able to tell the difference?
A psychic can do a lot of horrible things to a person's brain. I do, actually, think that mind control can be construed as rape. Mind reading cannot, but the victim doesn't know which has just happened. A skilled telepath doesn't leave traces perceptible to anyone but another telepath. So if the victim can't tell the difference, is there a difference? (Serious question, not rhetorical.)
I don't really think that mind-reading is totally comparable to the wiretapping analogy, either. I mean, yes, it's the most comparable thing I can think of, but it's not just my actions that someone's spying on, it's my brain. That's where I keep my me, and as such is infinitely more private (for me; YMMV) than my mere body. The idea of someone being able to go in and look through everything I've felt but not said, every silly dream I've had, every idea, everything I've never been willing to share with anyone because it's too personal and private to tell to the people I love most...I'll be over here. In the corner. Shaking.