And we all benefit through lower bid/ask spreads

"Market maker" refers to a "role" in a market. HFT is simply one way that role is fulfilled, in some markets (equities, futures, ...) but perhaps not others (corporate bonds, MBS, ...). No market needs HFTs to provide the service, but they exist because in those markets they provide a monumentally better (cheaper) service than their predecessors.

You don't need HFT, but those market makers lost to HFT on price. HFT is far far cheaper than the old market makers.