Layla4, first off, chairs are responsible for more than that.  They are in a position to influence and steer committees.  In this case her views were (in part) antithetical to the reason d'etre for the committee, so it makes no sense to place someone with these views in the position where they are able to influence the committee's work.

Second, regarding your comment about tie-breaking votes, do you honestly not see the inherent conflict with having someone with her views being responsible for breaking a tie, if and when the issue involving the very views that she espouses arises for a vote?