I go to college in Boston and was housed around Berklee, and I also agree that the billboard (recently removed, IIRC) was in pretty bad taste. I agree that we're missing the point here, but more so because messaging like that only seems to be counterintuitive and provocative and probably does more harm than good.
The billboard in question, when I saw it: https://www.stophandgunviolence.org/wp-content/uploads/2020/...