I too bristled when I heard POTUS repeated use those words.
He should have explained what he meant. That is, under the emergency orders in effect, he does, indeed, have dictator powers. Frankly, the statement that he, or any president, has authority over the governors scares the hell out of me.
He explained that the powers were those of the presidency, not him in particular, and that they were in the context of this emergency only.