It bothers me that we don't know anything about this shooting yet, and there's already a knee-jerk reaction:
"This tragedy again shows why we must continue to focus on the amount of illegal guns on our streets that make it into the hands of individuals who should not have them and continuously carry out violent acts in our city."
We don't know how many shooters there were, who they are, what guns were used, or if they were illegal or not.
According to this article there were at least two shooters, possibly more:
https://www.cbsnews.com/news/baltimore-brooklyn-mass-shooting-block-party/
"Police have confirmed there were at least two shooters and are investigating if there were any more. Police did not know as of Sunday afternoon if the shooting was targeted."
It's too soon to just jump to conclusions here.