I don’t think it was stupid. I think he was consciously enabling them:

Throughout his campaign and presidency, Donald Trump has been reluctant to criticize domestic terrorism and hate groups operating within the United States. The president has focused almost solely on foreign threats but the FBI and the Department of Homeland Security reportedly informed Trump months ago about the domestic threat.

In a May intelligence bulletin published by Foreign Policy magazine on Monday, DHS and the FBI pointed out that attacks by white supremacists on U.S. soil far outnumbered every other type of terrorist threat.

The agencies concluded that attacks by white supremacists “likely will continue to pose a threat of lethal violence over the next year.”