This is a literal example of lack of liquidity combined with fat fingers. And when stop losses activate, it can become an extreme example like this but huge wicks are not unique. The fact that it went so down also means that this fat fingering moron lost a lot of money. If it would be manipulation the price wouldn't just come back in an instant and no one in their right mind would like to use such an expensive and ineffective tactics for manipulation. In places that don't offer any protection against fat fingering and have low liquidity, you can potentially make a lot of money by setting lot of low buy orders.
I would still believe in such a version on some low-liquid exchange, where one order can empty the entire order book. But we're talking about Binance, where the trading volume is tens of millions. What other fat fingers? Do you seriously think that this was done by some crooked trader who accidentally pressed the wrong button? Obviously, it was not without the participation of internal market makers and their bots.
First of all, trading volume and good liquidity are whole different things, volume can be faked quite easily with thin walls, (most of the time by exchanges themselves). And sometimes even that good liquidity just falls short momentarily creating a short window to someone fuck things up. That got fixed quickly and as you can see the buy orders came back right away.
Entire orderbook for one pair can be destroyed by a bigger whale by mistake (especially few years ago). I personally know one whale what could have crashed one of the top projects while ago with all the pairs because he was one of the largest holders and obviously he didn't want to do that on purpose, but all you need is to make a drunken accident, that's Occam's razor for you, it doesn't need a conspiracy.
And i disagree about your opinion about WSB. I think it was good for cmc to stand with them in this case, the situation showed the need of decentralization and awareness was needed.