They probably asked your friends if the picture was you or not; they'd almost certainly be willing to do the verification if told it was to "prevent someone from impersonating you".
If you don't want to aid him, that's quite alright, but I'm not sure how OpenSSH balanced against his abusive comments to select users on mailing lists is somehow a net negative...
It's not like we're talking about Wagner's antisemitism vs his music here!