The Web site went live in 1998, any movie reviews aggregated for before that are not as accurate.
Of the others, I really shouldn’t comment because I have never been able to make it through Black Hawk Down and have no interest in seeing the others. There are of course several reasons to give them bad reviews and they aren’t politically motivated (I’m assuming that is what you are getting at here, not sure why as Star Trek is pretty apolitical from my viewing). From the bits I have seen and what I have heard, Black Hawk Down and Passion of the Christ both seem to be the worst traits of both (normally very good) directors. An Inconvenient Truth is the most likely to get a favorable review due to politics, but I’m not going to immediately disregard the possibility that Gore could make a compelling (if not totally factual) documentary.
Summer movies are almost always far more divisive than this one has proven to be on Rotten Tomatoes. I hate to go making bold statements, but I would bet nothing else released this summer will come close to that.
I posted that list because rottentomatoes is not very accurate about what is and isn't a good movie.
As far as Black Hawk and Passion of the Christ, they were two of the best ever made of their subjects, war and religious.