How can this possibly be constitutional?

While I am constantly weirded out by how seriously fascists take the constitution, it is ultimately not "real" in the sense that it doesn't define or restrict their actions.

Plus, the courts have very limited enforcement power and can often just be ignored.

And even if this is unconstitutional, and never passes, it's a screaming out to fascists that they can and should kill. It sends marching orders to the fash even if it doesn't hold the weight of law. Like how back in the Trump year's Trumps more or less open support for fascist street fighting gangs emboldened them right up until the FBI turned on them.