I`d say it`s more likely that men don`t review the bigger gals, regardless about how good they are, than anything to do with poor service. Most BBW fans would consider themselves to be a minority, and posting any reviews about BBW providers would be considered a fetishistic review of less relevance to the vast majority of the board.
As for the Mature Lee example, she received a lot of publicity due to a controversy, which had nothing to do with her BBW status.