When you use a state's right to promote evil slavery, you will lose that right.
Imagine the socialist Democrats create a civil war on the left coast. The army and patriots crush them. Would you be OK with the left coast putting up flags and statues for socialists after they lost?
Yes, it is their right under the First Amendment to do so. I do not have to like it or live where those displays exist.
You mean like the celebrated MEChA and La Raza is trying to do in carving out a section of the USS to be called "Aztlan"?
Is this Marine Corp general banning their flag and colors?
There is a statue of Lenin in Seattle.