True. But, how does Chainalysis know whether the coin is actually dirty or has a travel history from a service similar to the one in your signature?
That's their trade and they're unlikely to tell you how they know. They could of course be making it all up. It's not as if some tubby sheriff is going to know better.
But there are plenty of cases of moronic dark market traders sending coins straight to exchanges. And those Twitter hackers posted an address with previous transactions to exchanges. The criminally minded are just as lazy and stupid as the rest of us.
Even the more careful can blow it all with one slip.