I don't think American culture is too prudish - it's more a case of it being structured in-between extremes. On one hand, you have guys and gals who think nothing of leading a largely carefree existence, you've got the Spring Break fetishism, the porn industry, Reality TV and the whole social standard where we end up idolizing complete strangers based on their looks.
On the other, you've got groups who'd pretty much like it if women stayed in the kitchen, if Sundays were spent in service to God and especially *in fear* of God, who consider almost any kind of honest expression as being sinful in nature, and who view aggressive and domineering ultra-masculine dominance as being the only proper way to live.
In-between, you've got Industry and Commerce. There's money to be made out of being lecherous, just as there's money to be made by White Knighting it up for the sake of "family values". America seems to have lost the rather important midpoint or doesn't really care for it anymore. You can be a loving father or a Christian while still putting some time aside for some good, clean fun. You can be an atheist, have zero experience or very little sex-appeal, and still be a good person.
Thing is, extremes are fun. Just ask the Japanese about Hentai. They've got the same problems, though. Ejaculating or urinating becomes shooting milk through your nose, and the phallus is substituted for, well, anything that's vaguely pipe or cable-like, or tentacular in nature. You can't show something as natural as a dick onscreen, but you can subjugate make-believe female personas to otherwise degrading and humiliating stuff. That's A-OK. See the problem?
I don't agree with Bellard. You want to make a racy game? Go ahead and make one. You're not advancing the cause of gaming as an art form or as a means of personal expression if you're giving us a panty shot simulator - but you're likely to make some money off of it nevertheless.
Steam said no? No problem, option your work to some of the more racy software publishers in Europe, as those do exist. Back in the Minitel's glory days, you could access entire catalogs of racy games through your phone line. The Internet's replaced that, but the principle remains the same.