I think the problem arises from massive amounts of loans made to oil companies and affiliated vendors all down the line that were predicated on the belief that oil would stay safely above a minimum level needed to service those loans. Now oil is well below that minimum required level which means 100’s of billions of dollars in loans are about to default.
That, in turn, could take out the loaning banks, leading to a cascade type failure of the entire global financing scheme (being polite in choice of words, think of the adjective Ponzi).
Anyway, I think that is the problem, or at least the perceived problem with cratering oil prices.
OIl companies that didn’t plan for the possibility of such a downturn and banks that loaned those companies money should pay the price for their foolish decisions. During feasts you prepare for famines. I write this as someone who has invested in oil companies. They should have prepared for something like this. It doesn’t take a genius to know the Saudis weren’t going to stand by and do nothing while the oil shale industry made America an energy exporter.