Is the media just lazy here or is this part of an agenda?
The answer to the above is a mixture of the two. There are some media outlets, magazines, blogs, radio and television stations with an agenda that is political. For many of those, just as many of the comments in the threads on the topic(s) on these forums, the story is "******* Out of Control, Again".
There are many more outlets, however, where the agenda is selling cornflakes or subscriptions to the channel.
Violence and bad news SELL. People tune in. It's hard for a white collar (not necessarily white-skinned, let's not read that into it) reporter to stand in the midst of a riot and not report on the rioting. The time for pensive reports as to the causes is before and after that. When the rioting, looting, beating are ongoing, the story is the rioting, looting, beating. Most on-site reports that I've seen that are not "we now cut to the scene of the latest whatever..." do give the background and some explication of where all of this came from, or at least the immediate causes including the current case and the history of such incidents in Baltimore. BUT... they still get to "and now, some exciting footage of cops beating on people" or "here's some more thugs acting up".
It's what the media does.