That's very sad day for crypto, but probably it doesn't comes as big surprise, considering narrative that mixers is used for money laundering. Yes it's used, same as many classic fiat money laundering schemes like offshore companies for example, but they aren't doing anything against it. And as someone noticed in Chipmixer thread, Feds chosen interesting timining to announce seizure of Chipmixer - bank crisis that's going on in US now.
I skimmed through investigation, but haven't checked all in detail. It's very detailed, 60 pages of information and for me it's interesting that they show everything in public. It's like a message for remaining mixers in market - we're watching you..
From what I understand, there is just one man behind Chipmixer and as I understand, he didn't got arrested. It seems that NGUYEN worked really hard to hide his identity, but still he got caught by using PayPal...

I think it would be too much. Bitcointalk, same like Reddit was only used as platform to promote business, but it didn't got involved in money laundering