Signing a message from an old staked address would be a much better way of assuring members that indeed you are still in control of your account.
That's what I thought too, seems like a really good excuse for someone to use so they can be less suspicious when it comes to changing passwords and the owner, it's a thing that's got to do with human psychology, you cut some slack on people that got a problem that they share to everyone and you end up not being too cautious, but I do think that OP will eventually comply to this message signing request, I don't think it's going to be big deal right?