So you are calling them scam because how they generate bitcoin address? Instead of generating new bitcoin address it is directly asking to send bitcoin to one address only. Checked it and seems like it is true but don't see how they can be called a "scam" based on that. Maybe I am missing some point also so feel free to prove your point.
The proof is that it is always the same BTC address generated by the mixer so here is the scam in addition to that of the victims who lost money. So take chipmixer it is an always different bitcoin address with a key when we check the btc address the balance is empty. When you look at mixm.io's portfolio the address and not empty it already has money paid by victims. Try you will see you will receive nothing on return.
Because people who do not understand it is a general is who create it or already participate in the same direction this scam.