It shouldn't come as much of a surprise, really. High frequency trading is used to manipulate every other market on the face of the planet, so obviously someone was going to put two and two together and realise you can do the same with Bitcoin. The real problem is, how do you prevent it?
Government or consumer-demanded transparency. Don't expect the latter unless a bunch of people get screwed over first, though (and then it needs to happen roughly five more times, and then people will go to government instead of demanding it from the company). The real issue, I think, is that the "problem" is more dangerous than immoral, so of course, individuals being the arrogant fucktards we are, assume we can mitigate the risk, operate in the clear, and come out as the exception to guaranteed eventual implosion. Nothing to feel too bad about, really, though, nor some new plague on Bitcoin due to particularly shifty individuals at the top... banks pull this shit on a regular basis.
