Some people have big dicks. Some people have small dicks.
Some bodybuilders are compensating. Some bodybuilders are just adding more total package around their already nice "package".
We've shown here, so many times over, that you can't generalize who is, or isn't hung. Well, except that all blue-eyed guys, who are naturally smooth, live in northeast Italy, are French-speaking, and have attached ear lobes, because they're massive. That's been proven true countless times.
As an aside... I've seen first-hand how some steroids can cause ball size to change (my old room mate used to make a point of showing me, because he thought it was "funny" - he was strange), but his cock was always the same, the high end of average/low end of big (I didn't see it fully erect, because that isnt' why he was showing it to me). His ball size varied wildly, apparently depending on what kind of cycle he was doing.