This (a banned editor etc.) standing is not without precedence. This year WMF's Board election had one candidate which is permanently banned on the English Wikipedia. (There is the obvious difference he was up front from the start that he was banned on en.wp, and that he isn't actually banned on meta.) The election committee likewise decided at the time that it wasn't a good idea to retroactively disqualify someone that had met the candidate criteria already set out. I don't immediately recall whether in hindsight we would have set out better candidate requirement to have prevented him from standing, although I don't think so, along with similar reasons already stated on this thread regarding it being the community's job, and not the committee to decide who they want on the board.
While I'm writing this, as information for potential voters in this election reading this email list, I would like to state publicly for the reasons including but not limited to the topics of this thread, I would not be willing to serve on the board of a company intending to be the UK Chapter of WMF with the person controlling the account meta:User:ScribblewikiLover. So, either vote for him/her, or me, but not both as it would be wasting your time. :)
KTC