BLM and Antifa believe there is institutional racism, that stealing is reparations, and if a person of color wants to beat a white person, they should just lie back and take it and never fight back, that there is white privilege, etc.
Planned parenthood believes a baby is a mass of cells until the miracle of birth(or a few minutes thereafter), when it magically transforms into a human of unknown sex until it is old enough to make it's choice about what gender it is. . .
The Democrat party believes that Trump is mentally ill, colluded with Russia to steal an election, he's secretly a dictator, he's messing with the post office to steal another election, etc.
But no one asks Biden to disavow these groups.
Yet, Trump has to disavow every person or group out there that says something that sounds odd to reporters. I'll bet more than a few reporters believe one or more of the things I listed above, though none of them are actually backed by facts or by Science!(said in the liberal tone, the way they say it for effect).