Because of the Mad Love this fandom has for Rodney, I think people sometimes want to coddle and protect him to a degree that's a little silly. Because you're totally right! It is within Rodney's power to say, You know what, let's not do this -- either because he's not ready, or he thinks it'll be bad for their relationship, or he feels like John is being a dick to him, or for whatever reason. I'm not entirely sure in what world "We can either have sex or we can hang out like we always do, whichever" is psychological duress. *g*

It's only a "bad decision" if he's sorry for it now, if it turned out to be self-destructive...and I think interestingly, the story doesn't wholly resolve that question -- another thing I give it credit for.