I think he's making a whole lot of assumptions here that you just can't make.

First of all, let's not forget that there is a large degree of automation in bitcoin trading since, you know, there's an awful lot of programmers around. You can also look back and see all trading robots that have been posted to the forums alone where people literally download and let it run so you have a large population of users who don't know what they're doing just letting the bot do its thing. Since this is the same exact bot over many different accounts, they will all notice the same things and make the same decisions.

In fact, I used to use this knowledge to predict what the bots would do in a certain situation. When I saw that scenario playing out, I would take advantage of the bot's mindlessness and it was making me some pretty good profit. The bots have gotten pretty sophisticated now, and the market is large enough that the risk to me is too great. I wouldn't put it past a bigger player to be taking the same sort of reactionary trades against a programmed hive mind.