And mixer's receiving address is merely another peer in the network, no? Centralized mixers, like centralized exchanges, are merely providing a service for the community.
That's my exact point:
A "mixing site" is just someone else's wallet. Unlike exchanges or casinos, a "mixing site" is not a service since there is no underlying purpose for the site's existence.
That's merely according your own personal opinion. Because if the entity you call "the wallet" actually mixes their users' outputs well, then who are you to tell everyone that "there's no underlying purpose for its existence"? If it's a service and does the service well, then it's up to you to use it, or not to use it.
¯\_(ツ)_/¯