Everytime the word 'sexual' is used to describe an issue, the issue becomes controversial. The point is not that it was sexually offensive, it's that it is simply offensive.
If any member were to complain to me of an offensive avatar, I would take it into consideration. If it was indeed offensive (within reason), I would ask the user to remove it, then warn the user if he didn't respond, and finally, I would remove it myself.
I hope that my staff would do the same...and look at that, they did.
This argument is pointless.