"Bombs" is highly melodramatic. And at the speed that burned, it would be tens of miles behind an aircraft after the collision, and that's assuming that the impact didn't break up and spread the materials so thin that they weren't an effective hazard.

LiPos don't explode. They must be seriously mishandled for some time to even become relatively unsafe.

Yes, the chemical reactions are pretty vigorous, but it takes quite a lot of special cases to get it to burn.

It's not really an explosion.

The volatility just means the wreckage of the drone burns for a few seconds. That's not nearly as big a problem as the impact itself.