I am staunch believer in the moral and societal good of free speech.
Anonymous speech is far more dubious.
Like, protests seem valuable. Protests while wearing robes and masks however...
This is absolutely permitted in America. It is illegal in countries like Germany which have no strong free speech protections.
They're Klan Acts, because a bunch of guys in masks and robes marching through is obviously a threat of violence.
As a general rule of thumb, almost every time someone brings an edge case about whether or not speech is First Amendment-privileged before SCOTUS, SCOTUS rules in favor of the speech. (The main exception is speech of students in school.) SCOTUS hasn't specifically ruled on anti-mask laws to my knowledge, but I strongly doubt it would uphold those laws.
You don’t have to pontificate. The link was right there.
If you assume a just government that doesnt demand revenge for every petty slight, you are living in a fantasy land.