They're not a "winning player" in the usual sense. The casino wants players to bet on a certain outcome in some cases (in order to reduce risk, presumably) and therefore hands over the winning strategy on a silver platter.

I feel like the casinos just want those kinds of bets to be small. They don't want to over-correct in the other direction. By limiting these players that specifically make these kinds of bets, they reduce the risk of a big amount of money being bet in a short amount of time on the "winning" strategy.