If the business generated more than 12% in earnings per year, then it's not a ponzi. The difference between an obvious ponzi and whirlwind is that the mixer was clearly working, the unknown wasn't if the business was real but rather that no one could known whether or not it was turning a profit after advertising expenses.
That's the same 'unknown' as with tons of previous services that promised yearly returns in the crypto space. They were usually even higher, sometimes much much higher, which made them more risky / suspicious, of course, but there were definitely some with a seemingly legitimate and working real business behind them.
It's just that when you've seen it so many times you get cautious every time someone promises you free returns if you just deposit your coins with them (for whatever reason they claim to be making this money, at this point).
Do you know of anyone who has actually used their anonymity mining service though? Because to me at least, it looks like their advertisements of the alternate mining" campaign fell flat in Bitcointalk, so it is a bit reassuring to know that people here are not candidly throwing money at silly services like investors and crypto meme "traders".