I’ve been talking (ranting) about the horrible homicides of Sterling and Castile all day. I feel very strongly about the issue. Senseless, tragic deaths, which make me sad, indignant, and furious.

More senseless police violence. We need people who are poised under pressure, not people who start shooting once their fight-or-flight kicks in.

From your link:

“Their deaths isn’t something we should mourn.”

It’s not derailing if the shooting occurred at a protest about the subject of the article. In fact, it’s quite pertinent.