If the bitcoin community decide that what they have done is wrong and unconscionable, then the bitcoin community can instruct bitmixer to make amends that will satisfy the bitcoin community.
Either they claw back the mixed funds from the hacker. Or pay the outstanding bitcoin back to klee from their own pocket.
Otherwise, bitmixer are out of the bitcoin commmunity, as their criminality is not something accepted here. Although it feels like I'm the only person who thinks this way.
Or is the destruction of Bitcoin your actual goal?
The fact you use the term claw back is very telling of your state. You fear freedom and privacy - you want money that can be clawed back, again Bitcoin is not for you. Go back to the safety of USD and be happy and fear free.