Uh oh. When will presidential candidates ever learn?

As Twitchy reported, Rep. Nancy Pelosi’s daughter Christine was among the first to scold her “fellow white progressives” for saying that “all lives matter,” because it is received as “erasure not inclusion” by the #BlackLivesMatter crowd.

Presidential candidate Martin O’Malley, while being shouted down at today’s Netroots Nation panel, tried to assuage the audience by appealing to everyone.

If O’Malley read Twitchy every day like he should, he would have known that many of the more polite black supporters of Hillary Clinton declared she had lost their votes when she said that “all lives matter” while speaking in a black church. Hasn’t anybody read this sign that’s been making the rounds?

O’Malley certainly did consider his “gaffe” after the panel, when he confessed it was a mistake to have said that “all lives matter” and he meant no disrespect.

Also present at the panel was candidate Bernie “Get Off My Lawn” Sanders, who didn’t show quite the patience or contrition that his opponent did.