Sorry, but from a pragmatic point of view, having them up there was fucking stupid. Especially with the recent spate of murdered cops. That stunt certainly didn't garner them any more votes than they would have gotten from the same demographic, but it's a pretty good bet they lost some from others. Thankfully this latest Trump-Russian thing has diverted attention.
First of all, if anyone has a problem with the message that police and communities need to work together to stop the killings, then those people were never going to vote for HRC anyway.
Second, two of the three women who spoke did not lose their sons to police violence. Trayvon Martin and Jordan Davis were murdered by assholes with guns.
Please don't let the Derecs in our country frame the narrative.