Correction -- it's "Let's *dig them up* and shove them in the basement."
There are several villains listed that have been dead for years -- heck, Wally went to the read of the first Icicle's will!
If you don't want the supervillains bodies out there, get a court order for cremation. But a morgue -- which implies that the bodies are there and available for autopsy/dissection/research -- is just creepy.