I do agree with you that people shouldn't have been left stranded, because it appears that the airlines were obliged (by EU law) to provide/accommodation food and that some have fallen short of their obligations.
I suspect (although I don't know) that the reasoning behind the EU law is precisely because most individual travel policies exclude liability for "acts of God" etc. The airlines should be aware of the EU regulations and insure accordingly (or choose to take the risk, as we can infer Ryannair has done). The airlines seem in some cases to be arguing that "they couldn't possibly be expected to bear losses in these circumstances". The fact is, they are, and they should have insured against it. It goes without saying that airlines have far greater purchasing power when it comes to insurance cover than any individual.