I’ve been under the impression for some time that Sanders supporters produce more negative material about Hillary Clinton than vice versa. In an attempt to quantify this, I looked at the first 100 posts in the Bernie Sanders for President 2016 community and the first 100 posts in the Hillary Clinton for President 2016 community, and counted the negative posts about the competitor.
The Sanders group had 13 posts that cast Clinton in a definite negative light; the Clinton group had 4 posts that cast Sanders in a negative light. In general, the Clinton group seldom mentioned Sanders, and mostly posts positive messages about their candidate — new endorsements and so on. The Sanders group, in contrast, had, in addition to negative posts about Clinton, negative posts about the “establishment”, the “mainstream press”, and “political conspiracies against Sanders”. Posts mentioning Clinton, in general, are much more common in the Sanders group than posts mentioning Sanders in the Clinton group.
There is nothing scientific about this — the posts in both groups change frequently, and I was just using my own interpretation of what was negative. The relative mentions of the competing candidate are pretty objective, though.