> Lol, as opposed to all the other actors in the economy who provide a service.

I see what you mean and there may not even be a visible difference from outside.

But I think there's a big difference between "I'm going to make money getting grocery products as cheap as possible and selling them as high as local market can handle it" and "I'm going to open a grocery store in an area which doesn't have it yet and make money providing products to people". Effectively they're the same and some people may think of it as the first case.

I just don't believe anyone doing HFT cares one bit about the rest of the market. They are in it to make money. It just happens to lower the spread. If there was a way to do it by making the spread larger and pissing everyone else off, they'd still do it.

Different example in real life in some countries - homeless people collecting glass bottles from the street so they can return them and get some change back in countries where recycling cost is added to the price by default. You're paying for it when you're buying a drink and not returning the bottle yourself. They get money for cleaning the street. But it just happens to be connected - I wouldn't say you're paying the homeless for the street cleaning service.