I have to agree with the others ... I doubt you have a compensable claim against DL ...
So to that end, if you wanted to pursue it, I'd do so with limited expectations and recognizing your most probable outcome will be, as noted earlier, a small travel credit or mileage credit..
Bags aren't handeled as carefully as they possible could - no arguments there.. I've done that job before early in my overall career..
Do bags get damaged by human "throws and drops"? Yes, absolutely... However, I will also say that they are *more likely* to be damaged during some phase of the automated handling process ... and that's simply recognizing that from the moment your bag is tagged and placed on the conveyer belt at the check-in counters, to the moment it emerges at the reclaim belt, there is more automated handling and automated processes than there is human interaction.
Those automated belts, conveyors and pushers are very, very strong and will sheer off, nearly any object caught in the machinery - and so with near zero resistance.. I've seen plenty of handles, wheels, straps and other things that end up under the machinery once they've been broken off.
Again, this doesn't say humans movement couldn't be more careful - it could .... But it does say that bags today are moved more by automated machines, than people.
I do think you have an expectation to get your bags back in largely the same condition you tendered them - less nominal wear and tear - but just like it is other automated processes- sometimes that goes wrong.