Maybe the big tent, all inclusive GOPe is scared of her. She’s very popular, hard working and effective. Who would want someone like that associated with their party? Not the GOPe, that’s obvious enough.
File for future reference. Richard Nixon was not invited by Goldwater to speak at the 64 Convention in(are you ready??) San Francisco. But he did make it to the convention 4 years later and gave the convention’s final speech.