My logic is more about sustaining productive debate. When the eventual Latino kills some whites in revenge for El Paso, will there be intelligent discussion about gun control, mental health, etc, etc? No. It'll be, "How's it feel lib s that the shooter was Latino, an immigrant, and a supporter of Bernie Sanders!" Then the left will counter, "Yeah, but most of the attacks carried out were by white nationalists over the past few years." Then, "Keep deflecting lib s. You own this one." And no one will talk about any solutions. White nationalists will also feel vindicated that, "they aren't the only ones." And will use the attack to stir up propaganda fodder for the "race war," they want, meaning more potential radicalization.
Yes, white nationalism should be called out at all times, but in these mass shooter cases, I don't think it's wise to browbeat the point into oblivion.