The head of Republican Women for Hillary, who spoke at the Democratic Convention, was not just any woman. She is a lobbyist for the US Chamber of Commerce, which fights against more or less everything that would restrain plutocracy.

Her personal job is campaigning against the universal single-payer medical system that Sanders advocated and that Clinton now opposes (though she was in favor of it before).

I see nothing wrong in boasting of support from Republicans who can't stomach Trump, but support from people in the US C of C is a sign that a politician is on the wrong side.