This is a bizarre bug. I got an email from another admin on jawiki, who said they coudln't move 勝利の女神_(曖昧さ回避) to 勝利の女神 per a requested move (Click here to go to Special:Movepage). The destination page is a 1-revision redirect to another page, which ought to be overwritable with the delete user right.
I myself gave it a try but I couldn't either, because of a permission error. I tried the same thing on testwiki but that worked.
Update:
It seems like it's systematically impossible to move a page to another existing page that's redirected to yet another page (i.e. can't move A to B when B is a redirect to C). I observed the same bug on testwiki.