Good mixers will completely break the chain between inputs and outputs.
Doesn't this mean that somebody else will receive coins (from the mixer) from the "tainted" "source"?
Why are mixers legal? The only purpose I find on them is to money launder. They are literally useless if you don't have anything to hide.
You like people look into your pocket? Is the content of your bank account shown on your FB wall?
Do you use curtains at home? Is your door open?
You always have something to hide. I remember that at some point somebody came here asking for advice since he was threatened by somebody who knew him and who has seen how many bitcoins he owned.