I'm not sure about whether or not my theory is correct, but i'll give it to you and let you decide.
1) I am under the assumption that fouling is a hidden attribute based on previous discussions
2) I believe that math being involved means that you can have a guy foul more often in some situations than others. If one player is high in fouling and is the go to defender, then he will likely foul more often than he otherwise would against a lesser weapon. This is why i experience fewer fouls when the opponent is playing inside and not training guards at the PG position that are a reasonable amount of the way through development. If i face some weaker player who does not see a lot of action with shooting the ball, then there will not be as many shots for my player to foul. They can still foul a lot late in the game, and can foul a bit on non-shooting fouls, but i feel like this is basically a more random occurrence.
3) In conjunction with point 2, i think that hrudey is correct to surmise that higher SB can create fewer chances to foul. Similarly, passing reduces offensive foul opportunities.
4) a 3-2 zone likely impacts the fouling tendencies based on what the opponent runs. If they run an outside offense into a 3-2 zone, then it is likely that they would create more situations for fouls to occur on a highly aggressive perimeter player. If they run look inside instead, then most times the highly aggressive player will be preventing passes and not shots, which statistically is where the bulk of fouls occur. That is why some might experience a better foul tendency from their player when running a zone, while others do not.
5) a lower team defense is also likely to create a situation where there are less fouls to be had. Fewer rebounds would occur, and assisted shots tend not to see the same rate of fouls as the contested shots do.
In theory though, i would rather know the guy i am getting isn't highly aggressive. You tend to have to paint yourself into a corner with strategies and masking his foul tendencies rather than being open to being more strategic and being able to outgame the opponent.