I definitely think that Rick Santorum's quote was (probably accidentally) revealing of conservative attitudes about sex. In an attempt to explain why he supports banning gays in the military but doesn't want this to be characterized as bigotry, Santorum said this:
I — I would say, any type of sexual activity has absolutely no place in the military. And the fact that they’re making a point to include it as a provision within the military that we are going to recognize a group of people and give them a special privilege to — to — and removing “don’t ask/don’t tell” I think tries to inject social policy into the military.
What made this comment so eye-rolling is that he's functionally trying to claim that people who have any kind of sexual activity with the opposite sex are already banned, and therefore letting gay people in is a "special" right. That's literally the only way this makes sense. But in a fucked-up way, I think he probably does believe a variation of that. There's just a deep-set sense with the religious right that sex is just inherently perveted. This is a statement of a man who probably begs for forgivenness every time he ejaculates. That's why they insist that contraception even within marriage is an iffy proposition—if you're going to be so dirty, you should at least pay for it somehow.
Which isn't to say they see straight and gay sex the same. It's more like straight sex is the marijuana/alcohol of sex, and gay sex is the cocaine. It's more taboo in their minds, so it's somehow more sexual. So he's approaching it like you would if you were a big enough dip to say, "Drinking and drugging has no place in the military," with the full understanding that you'll look the other way when it comes to the drinking, but you'll boot someone immediately for cocaine. So pointing out that Santorum has 4 kids with his wife sounds, to him, like someone doing a line claiming it's the same as someone who has a glass of wine with dinner.