Because people find it offensive
And many people, probably the majority, are offended by the efforts of a minority to “erase history” and police their thoughts.
If not for the renaming of the two city parks by two local politicians, and their attempt to remove the statues, the protests would not have occurred, and there would have been no violence.
The fact that some anti-semites support a position does not make that position wrong. President Trump has the wisdom to understand that and the courage to act on it.