I would have thought that if potential candidates are put off by this then maybe they are not suitable candidates anyway (ie thickness of skin required )
Make no bones about it, if you think the verbal here is bad, you should see the regular abuse that the BoD has to deal with.

Anyway, here are some good reasons in my mind.
Prior to each successfully nominated candidate accepting that nomination in early Feb, they may well with to gauge the level of support they have, or indeed determine whether another candidate is perhaps more suitable or appropriate.
While we have a surplus of armchair referees, we are not exactly blessed with a surplus of volunteers for most positions. Early postings usually help other potential candidates to throw their hat in the ring publicly before the closing date also.
This is not a game, it is the future running of the club at stake. As you know, there is no personal gain from being on the BoD.