how dmca claims are being handled is not on the GMT/NAT's scope tho. once osu! receives a copyright infraction notice on the
copyright@ppy.sh email, going forward all the concerns are going to be handled by... peppy himself mostly iirc (don't quote me on this btw as i'm not 100% sure).
back to the topic itself, this behaviour is actually intentional — this limitation has actually been put in place from osu!'s very early days in order to prevent people abusing the "Upload Beatmap!" button over and over :
either way, if you need your WIP/Pending beatmaps deleted for reasons such as "accidental duplicate upload" or the likes of it, feel free to ask any GMT or NAT members to delete it for you. as long as the request is valid and sensible, we would be more than happy to help. 🤍