Shelters are overworked and understaffed, and a dog with known aggression problems is likely in for a bit of a stay - she’s not dropping it off at a good home, she’s just passing the problem to others without making any attempt to take care of it herself - and, by doing so, guaranteeing that the dog is going to be pretty hurt and miserable for at least some period of time. When you take responsibility for a dog, it is your responsibility for life - even if that includes finding it a new home.

OP didn’t even attempt to rehome the dog, her first response is to drop it at a shelter so it’s someone else’s problem. Except this is OP’s responsibility and she’s an asshole for not even trying to do the right thing. It’d be different if OP literally could not keep the dog in her home for some reason, but this just sounds like OP isn’t willing to be inconvenienced by trying to do the right thing for her dog. These issues didn’t exactly spring up on her out of nowhere.