I'll be perfectly honest. I don't think that absolutely everybody who plays this game is a wannabe rapist. I don't think that there's necessarily a correlation between people who do this "fantasy" stuff and what they'd do in real life. If that were the case then we'd all be going to hell for getting a kick out of watching our people run around like lunatics when the kitchen bursts into flames in The Sims.
I just think that at some point things stop being entertainment. Film can be used for a lot of things, not just movies. But even some fictional movies, traditionally intended to entertain, tend to jump a line where I find it hard to call it "entertainment." The same can go for video games.
This and many other hentai games I liken to slasher films. If Friday the 13th actually happened I think every single one of us would be shitting ourselves. That is not something we want to see. Now I'm not particularly a fan of slasher films but I can understand that it's a brand of entertainment that works for a lot of people. These fans can separate the fantasy of the movie from how they'd feel if it were actually unfolding right in front of them. And I'm sure most of the people who play RapeLay would be horrified if they saw a comparable event happen to their next door neighbors.
So, no, I don't think fans of hentai, even if the hentai involves rape or pedophilia, are necessarily bad people who are rapists and pedophiles themselves anymore than I think that people who play GTA are all closet mass murderers. I do, however, think RapeLay and comparable games are in bad taste and I wouldn't produce one myself.