I suppose for daring to campaign and not caving to the PC crowd.
This is what he said:
I also want to mention something about the events this evening in Chicago. This is a sad day. Political discourse should occur in this country without a threat of violence without anger and rage and hatred directed at each other. We need to learn to have disagreements without being disagreeable, to have disagreements while being respecting human beings on the other side.
Earlier today over thirty people were arrested at one rally. And then tonight as violence broke out the rally was canceled altogether. Now, the responsibility for that lies with protesters who took violence into their own hands. But in any campaign responsibility starts at the top. Any candidate is responsible for the culture of the campaign. And when you have a campaign that disrespects the voters, when you have a campaign that affirmatively encourages violence, when you have a campaign thats facing allegations of physical violence against members of the press, you create an environment that only encourages this sort of nasty discord.