I don't know. Is it helping?

We don't know what google are doing with pages like that -- there have been very vocal noises in all forums about directory pages polluting the search results (exactly like the ones on your site) --- so if Google was listening and considered it a real problem you could assume that they may somehow be doing something about it (or at least trying to do something about it) --- but we don't really know.

If its not helping, then maybe remove it for a few months to see what happens - you can always put it back later.

CBP