Hillary Clinton’s speech made the point of Trump’s racism, and then developed that point with factual evidence — much of it direct quotes from Trump himself.
This is how you take down your opponent. With facts.
Contrast that with Trump’s attacks on Clinton. There’s the whole “Crooked Hillary” thing, the whole “Hillary is so ill she’s dying” thing, and other baseless accusations that Trump can’t back up with anything of substance.
It’s no wonder that the establishment Republicans are silent. Embarrassed people often are.