Mixers are not illegal, even when United States have strict rules that mixers can not abide to
Unfortunately, for centralized mixers at least, you're wrong. In the US, you're prohibited to run a non-regulated money transmitting service; and that's pretty much what a good Bitcoin mixer is. Anonymous and it involves and intermediary who will transmit money. However, that does not apply on every country, and it does not mean decentralized mixing is illegal.
This is certainly the bottom line. The US (as well as EU) will also define money laundering to be whatever they want it to be, even with the rest of world not quite in agreement. Generally, any unlicensed money transmitting service will be considered money laundering if there is no KYC in place, even if not really any different than going to a shop with "dirty cash" and getting change that's "clean" from a vendor.