I don't think “emboldened" is the right word for this obscene and racist tirade. Perhaps one or more of the following:

Frenzied.
Violent.
Frustrated.
Enraged.
Berserk.

@gleick

"... seems emboldened by ..."

Remember when they said they couldn't use the word "lie" to describe Trump, because that would presume to know his internal mental state?