Peter's experience comes closer to mindrape, but Xavier's is a threat of mindrape.
Simply reading someone's mind isn't mindrape. There's a reason it's called "mind reading."
Mindrape is forcing someone to perform an action or actions (typically reliving memories, but sometimes more) for the mindrapist's jollies. So he/she can feel power over the victim.
Rape is forcing someone to perform an action (typically sexual, but sometimes more) for the rapist's jollies. So he/she can feel power over the victim.