First, thanks for taking the time to comment here, I really appreciate it (also thank you for the upvote, quite unexpected).

As for witnesses not reacting, I did my best to adjust my bias, but I'm only one out of 100 and not even in top 50.

I am with you 100% on the volume thing. I have been fantasized about the following theory, though, I don't know if it's real, but, at some point, it may make sense.

Let's start with a volume of $40 million equivalent of SBD. Bittrex says all transactions incur a 0.25% fee. So for trading $40 million, one would have to pay $100,000 in fees. That's just for changing hands of SBD for BTC in Bittrex (moving around SBD between STEEM accounts is free, as we know). So $100,000 for moving around $40 million.

If the profit made by pumping SBD twelve times higher is relevant, I think this cost is very small. Proxying capital through an overvalued SBD can lead to profits probably 10x higher than "normal" STEEM buying.

I'm not saying this is what's happening, I'm saying this is plausible.

But whoever did this probably made a lot of money.