Some political/philosophical frameworks are extraordinarily resistant to frank discussion. Down-voting and shouting-out are the way that proponents of those frameworks deal with any uncomfortable questions that may at all detract from their presupposed conclusions.
Even though your comment was really innocuous, it implied that maybe the study was wrong. Maybe hard work and intelligence are the prime factors in success vs what happens to be in your bank account at the moment. Some people can't handle even that implication.