I don't mind the speculative aspect of it so much - there's legitimate economic reasons for that to exist, and fills an important market function - but I do have misgivings about trades being filled algorithmically rather than by decision of a human agent.

On the other hand I'm not sure how you police it, because some home-investor with a trading program that kicks in and saves him from losing several thousand while he's in the bathroom is engaging in algorithmic trading too, and I wouldn't deny an individual investor such safety mechanisms.