I don't think that's correct. We have always had market makers: people who trade purely for profit. They grab stocks in anticipation that others will want them at a higher price. So, if I own stock, and you own stock, instead of the stock going straight from me to you, it's more likely that there will be a market-maker inbetween us.

The benefit of this is that the chances are small that you and I will be trading at exactly the same time. So, I say "I want to sell this stock," and a market maker buys it. Later, you say "I want to buy that stock", and you buy it from the market maker. The market maker makes money on the profit of the sale. So, I may get a little less, and you may pay a little more. But, it means that when I wanted to sell, someone was there. And when you wanted to buy, someone was there. That's what people mean by liquidity.

So, back to HFT: the losers are the conventional market makers. The guys in the pit who used to shout-out buys and sells.