Being able to distinguish between fantasy and reality is extremely important.
If someone can't compartmentalize those two things, then they're going to have a real tough time in life.
I can imagine jumping off of a building, or mentally put myself in the shoes of someone being shot. Does that make me suicidal?
If I'm in a bank and envision myself robbing the place, should I be thrown in prison?
Thought crimes are not crimes, they're thoughts. Being able to share thoughts with somebody is vital to our humanity.