For someone who gets paid to post and earnings are sent through the gambling site (Bitsler) like me, I use a mixer because my local exchange site does not allow BTCs coming from gambling sites (they will suspend my account or close my account) and known HYIPs that's why I am dumbfounded by Bitmixers decision and might look for other alternatives that offers same service with same level of trust earned by Bitmixer.
If Bitsler doesn't allow BTC directly from a gambling site, then first split the BTC from the gambling into another bitcoin wallet address prior to remitting it to Bitsler. It's not rocket science. Surely, Bitsler doesn't look at all the hops a transaction made prior to deposit, do they?