Does the population around you have a hard time keeping their genitals from crashing into each other accidentally?
Well, actually, a rather large number of humans throughout history have had a spot of trouble controlling their genitals, yes. Humans are, er, far from perfect.
I've heard some weak-ass excuses for infidelity before,
With Gardasil, by far the primary issue is sex before marriage, not adultery. I'm not sure where you're getting that from - certainly not from anything I actually wrote. Did I miss something in the previous comments?
But I'm going to continue the car analogy. Our oldest is learning to drive, and we're teaching him to be careful, cautious, and defensive. Not to take stupid risks, etc. Of course, most parents do that when teaching their kids to drive. And yet, kids do impulsive and stupid things with cars every day. (Heck, so do adults.) So we're also teaching him to use his seatbelt. Even if he does everything right, someone else could do something terrible. (I'm sure you can't imagine any analogy to sex there, right? Something about involuntary sexual activity even if someone's being sensible? There's a word for it...)
I certainly want my kids not to make mistakes. But if I can minimize the consequences of mistakes - particularly preventing long-term and/or fatal consequences - I'm going to do that. You can disagree as you choose, I guess.