Random question

Is it just me, or do John/Rodney fics tend to default to either (a) John's been repressing/ignoring the part of him that likes men and not had sex with one since he joined the air force or (b) John's been completely straight until now; while John/Cam fics tend to default to John's been having sex with men (as well as or instead of women; and who may or may not include Cam) but keeping it secret since he joined the air force?

Maybe it is just me, but I'm scanning the John/Cam fic I've got tagged, and I can't find any where either (a) or (b) are true for John (Cam's a little more complicated, sometimes) but can think of plenty of John/Rodney where (a) or (b) is off the top of my head.

And I guess my real question is less 'is this true?' and more 'why is this?' Because John's got to have a thing for scientists? Because Rodney's just that awesome that John would change the habits of a life-time for him? Because John/Cam people have an air force pilots kink (I vote that one, personally)? Because it's a lot easier to hook John and Cam up if they've been involved with other pilots (or indeed each other) before (though if it is that one, surely it's easier to hook John and Rodney up if they've been involved with other men before?) Also, now my own habits are showing, because of course everyone doesn't write John having only been involved with other military guys before, unlike me.

No, I don't know why I'm suddenly contemplating this question-too much time trapped in my parents' house? Family induced insanity? Who knows.