Part of that is that the Reds just got swept by the Brewers. Public perception of the Brewers is still as an "awful" team. Brewers were my pick for 3rd place in the NL Central at the beginning of the season. Surprise team, imo.
Also, St Louis lost 2 close games in a row to the Braves. People usually jump on teams like STL, Bos and NYY after they lose 2 straight. "No way they lose 3 straight" type thing