Well, surprised is not the right word. I do think - despite the reasoning for the riot being different -that the coverage is fundamentally different. no media outlets ever make the logical leap from sports riots to greater cultural or community issues. the link that perhaps sports-fandom is overblown and cities need to stop catering to pro sports franchises, etc. ... you never hear that. but when it's a riot like in the case of Baltimore, you do hear about a "lack of accountability" from that community, doubting the sincerity of the reasons for the riot by focusing on the looting/property damage aspect of it.
I suppose what would end this disagreement is a study of the number of arrests, coverage, etc. after a sports riot that involved a majority of African Americans vs. one that involved mostly whites, like an NHL championship. I remember reading about how the 1984 riots in Detroit after the Tigers won were seen as an example of how far Detroit had fallen under Coleman Young (i.e. under black leadership). someone could take the time to pull coverage of sports riots and see what weasel words make their way in to describe them, depending on the racial makeup of those rioting, or "celebrating" ... as the case may be.