If you had actually ASKED the Sioux of the Black Hills about this, you’d know they’ve told pretty much everyone “yeah we don’t like Mt Rushmore, we don’t like Crazy Horse’s relief carving either, but we think destroying them is more disrespectful than just leaving them to fall apart on their own.” Like, this isn’t an uncommon thought. It’s just more complex than “blow them up”.
Blowing up cellular and electrical infrastructure is BIG in white supremacist communities, the idea being that somehow these acts will push white people to an open race war.