Apology For 'Idiots' Election Ban

I read a story in the news today stating that Bournemouth council has apologised for banning "lunatics, idiots, deaf and dumb" people from standing for election. Apparently this wording was used in an information pack issued to candidates in Bournemouth, stating that the above were disqualified from standing.

An electoral services officer has said that the terms were from election law written in 1766, and have since been amended. He added that such language is unacceptable today, and that his council treats all people fairly regardless of the following:

Sexual orientation - fair enough.
Age - fair enough.
Religious belief - fair enough.
Disability - fair enough.
Gender - fair enough.
Race - fair enough.

No mention of idiots. What about the idiots? Are they not allowed?

Why can't we have idiots in power?