I agree, I wouldn't play them or buy them. While I believe it's disgusting, to me it seems silly these days considering what these are, porn games on an Atari 2600. That being said, it certainly was nothing to laugh about back then, but now, I feel it's seen as more of a joke than anything controversial. While I certainly laugh when someone mentions these games, I myself wouldn't play them since I'm a Christian and even if I wasn't, I still think they're sick and that this isn't the way that people should view a member of the opposite sex.
What I find interesting is how many of these games came out, and not all were Mystique and Playaround. There was one called X-Man by some other company and I believe there was at least one more. Also, Playaround made gender reversed version of some of these games. Seriously, these guys were huge perverts.
In general, I don't care if other people wanna try these games out, but I'd rather avoid them no matter how silly or collectible they are. There are better rare games out there like Frogger 2 Threeedeep, Swordquest Waterworld, and Quadrun. Still, whether we like it or not, these will forever be part of video game history.