I find it amazing that sensible people still think that any problem they encounter has to be the fault of someone and that compensation can be claimed.
It was not Ryanair's fault that the airspace was closed. If you were at your home airport you could have gone home and if you were away you were stranded, but that is not Ryanair's fault. Yes, perhaps more could have been done voluntarily by airlines, but they do not have bottomless bank accounts and with a lost cost airline, you expect minimal service over and above what you have paid for.
I once ordered a specific type of rental car for a family of five plus large amounts of luggage. When I got to the desk I was given a much smaller car and the excuse was pitiful. I got annoyed and eventually it was swapped over. But, as has been said before, if the authorities had banned driving how could I expect the rental company to help me?