Coincheck hack

Hello there, I know I have made a post about this already, but the Coincheck hacker’s funds are tainted through a mosaic correct?

If so, how is he/she able to launder it through the dark web? (according to CCN about 40% has already been laundered)
Surely no one would buy any NEM from them? Have they found some way to get around this?

I just find it worrying that the security measures taken are not working.

Any thoughts/ideas are deeply appreciated. I am curious more than anything else.