He called them out repeatedly on the harm the shit they're doing will cause ordinary Americans. This will resonate with people who don't like that party's self-assigned role as corporate servants.
I especially like how he baited the RepubliQ hecklers and made them look like complete assholes.
And Trump stumbled onto the stage--even if he only peels off 5% of RepubliQ voters in his MAGAAAA (Make America Great Again Again Again Asshole) campaign, that'll doom that party's chance in the Presidential contest and all the down-ballot elections that aren't held in redneck shitkicker states as well.
There's light on the horizon!