never said MM's should be obliged to be waiters or eat up a collapse. but yes, they will provide liquidity as long as they can make money.
Quote from propseeker:
market makers behaved as they always have: provide liquidity until they're stuffed to the gills, and then step away. this will never change. you can't regulate someone to go bankrupt just so some idiot can dump his wad on you. that's not how markets work.