And how do you know that that the Bitcoin mixer you decided to use is not actually operated by the FBI and that they are actually keeping a private log tying bitcoins in with bitcoins out?
This whole argument is stuck in 2012. Lean not on your own understanding and look at the technology thats out there.
[1] https://en.m.wikipedia.org/wiki/Mixmaster_anonymous_remailer
As for the hostile mixers, I'm afraid I can't offer any solution other than to rely on reputation. That said, it is rather telling that bitmixer.io is closing [https://news.ycombinator.com/item?id=14843373]. It may not be safe to run a mixer; the feds may come after you.