If a drug dealer is seized for pushing drugs and also at same time it was discovered that some Scammers give funds to him to run his business, what should happen to the scammers if found and could you say that the drug dealer was awear or not awear that the funds he is getting to run his business is from scammers?
Miners are also aware that some of the transactions they mine come from scammers, and thus take a commission from illicit activity. Does that make them scammers? No.
The fact that you think a mixer is a scam, just because it uses scammers' funds, means you've misunderstood the definition of a "scam". Let me quote it:
A scam is a fraudulent scheme or fraudulent activity conducted by an individual or group with the intention of deceiving people out of their money, personal information, or other valuables.
ChipMixer, and every other similarly working mixer, is the complete opposite of scam. Ensuring privacy for everyone, and therefore for guilty people as well, is what a mixer is all about.