MMs don't "facilitate" anything, they take one side of a trade. A broker facilitates a trade, a MM takes a side of a trade, pretty much by definition. There are no MM on the vast majority of the SSF contracts, and if you post a limit order it won't be hit by anyone unless you're way out of market to your disadvantage and someone happens along to see it.
MM's facilitate the market by giving a two-side quote to trade on. SSF's are illiquid, hardly any trades and therefore uninteresting to MM's who make money on volume x spread.
So it's a bit of chicke/egg thing, where a tight market in SSF might eventually draw more volume and make it interesting.
What @i960 probably meant was that MM's do quote on SSF's in the brokered (off-screen) market, which normally gets more volume and interest and therefore is more interesting to quote on. By giving tight quotes on-screen, as a MM you lose a bit of negotiating power since there's already a market given... although Futures are usually pretty straight fwd to price/quote.