Does the fact that Osama likes the porn diminish the love his followers have for him, because he partakes in a western way of life?

No. Because they won't believe it. He has them pretty much brainwashed. If you can convince someone to strap on a bomb and drive into a building, you can pretty much convince them of anything. I am sure, if they even know about it, it will be spun into "the western world lies". And it will give another idiot a reason to strap on a bomb.