We have the ability to warn people about weather quickly now, we understand what occurs on a delta in storm cycles, the skills to provide and rebuild are world wide, most countries now have the infrastructures in place to warn and move people away from harm.
Death tolls have decreased over our lifetimes.
Disaster warning, planning and relief is no longer just a western ideal. Thailand, India etc have come a long way.

There is a clause in the UN charter that could be invoked, but forced humanitarianism doesn’t make any more sense than the Burmese government’s paralysis. Human rights are not a concept.

The Red Cross was allowed in, they are finding it tough going and they also have locals they have trained.

Not warning the population about the severity cyclone is one thing, the public health catastrophe is, as you say, insane.