Saying that isn't really a logical argument on bitcoin being used to launder money. You are basically saying, well they also launder money which doesn't change the fact that btc can be used to clean dirty fiat. But any medium of exchange can be used to launder funds.
Don't get me wrong, not saying it should negatively affect bitcoin as currency but argument wouldn't fly on anyone with a brain
Try this one on your brain for size:
Dude with a hat goes up to other dude with a hat.
"Dude! You're under arrest!"
"Why ?"
"You're wearing a hat!"
"Get bent."
Money laundering can either be good or bad. It can't be good when the gov't does it but bad when some random party not in the old boys' club does it. Anyone with half a brain can see that.