I know what would definitely prevent Mixers from ever being used by criminals again. And you do too. It is the universal crime ending answer.
Know Your Customer!
I know you are being sarcastic, but I wonder if some of them seriously think this. I know they have been trying to push for KYC in more and more areas, but for some kind of content it does not work at all and for preventing crime relating to crypto even less so. It is one thing to push these ideas forward maybe for hidden malicious reasons, but it is another to actually believe in such absurdities.
He's not being sarcastic. There is actually a proposed law for a mixer to be considered legal. They need to register as a money-transmitting service, which will require them to take customer information, which includes, but not limited to, the identity of the customer transaction record and anything that can help them easily identify a person which defies the true purpose of what the mixer is being used for, and you and I know that's not going to happen so mixer will always be considered as a money laundering tools by them.
As consumers increase their use of digital assets for payments, individuals
may want to use mixers to maintain more privacy of their consumer spending habits. In addition,
digital asset services that take custody of user funds and accept and transmit value are currently
required to register with FinCEN as money services businesses (MSBs), maintain records, and
file suspicious activity reports. This includes custodial mixers, which—when compliant with
recordkeeping requirements—could provide unique information such as customer identities, off-
chain data on transactions, and behavioral patterns related to illicit digital asset flows upon
request to regulators or law enforcement.
REPORT TO CONGRESS FROM THE SECRETARY OF THE TREASURY ON INNOVATIVE TECHNOLOGIES TO COUNTER ILLICIT FINANCE INVOLVING DIGITAL ASSETS page number 8