Bitcoin mixing is like a double-edged sword that can be used for good and bad, depending on the person using it. So actually, what to chase are bad people who use bitcoin mixing for bad things but it won't be easy to trace them because they are also smart in hiding everything.
I understand the need and protection about it, what if I go to a casino with a million dollars, gamble a bit, and then take it out? I could literally cause a trouble with it and then I could end up with a laundered money. By that time when I withdraw if anyone asks where I found it, I could just say I won it at a casino. This is why laundering on gambling is common and it is easy, and that is why most casinos started to ask for KYC as well, it is doing fine and should not be shocked at all.