I don't think it's mind rape. I mean, it's a little questionable to force someone to have these memories and experiences. But I don't think it's unreasonable to say, "Hey, can you spare 20 minutes of your time to remember our civilization now that we're all dead?" I mean, it's hard to be angry it, when you put it that way.
As for the pointlessness of the scenes that snap back to the Enterprise -- I disagree. Those scenes had a very important role of defusing the suspense in the episode. You can't have your audience going through an episode like this wondering what's going on and if Picard is in danger. They did the same thing in "Far Beyond the Stars" when Sisko had a small vision first and then it flashed back to the station so Bashir could tell us that Sisko's brain is behaving the same way it did the last time he got visions from the Prophets (in "Rapture"). These episodes aren't about rooting for the character to get out of the visions, they're about the audience getting involved the drama of the new reality the character's experiencing.
"Frame of Mind" is a good counter-example. It's about trying to figure out which world is real and getting back to it (and the twist is they're both fantasy). But if "Frame of Mind" was about exploring the dramatic possibilities of madness, you would want to let the audience know what was happening to Riker so they could stop wondering and enjoy the drama.