Why can J. D. Vance change his mind, but not Kamala Harris?

Kamala Harris clearly said some things 4 years ago that she now claims she no longer believes in or supports. Conservatives seem to have issues accepting this, that she changed her mind.

In contrast J. D. Vance called Trump "America's Hitler". The conservatives seem to have no issue believing that he no longer thinks this. They accept that he changed his mind.

Why are they willing to accept that their. VP candidate changed hhs mind from the past, but not Harris?

Why can J. D. Vance change his mind, but not Kamala Harris?
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