Re: How can this be?
"Even minor damage to an airframe or engine will result in the craft or engine being removed from service while checks and repairs are made - this is very expensive and drone operators should be 100% liable for any damage caused."
Good point well made.
The same principle of recovering the costs doesn't readily apply to bird strikes, which is one of several reasons why busy airports often invest in systems (people, recorded noises, live predators of the feathered kind, etc) to reduce the risk of bird striike. Prevention is much better than the alternative.