> You realize that the origin of their changing stance is because they got someone killed, right?

The ACLU didn't get anyone killed, violent right-wing individuals did. The right to have a political protest rally is enshrined in the Constitution.

Consider the looting and rioting that took place following the George Floyd protests. It would be absurd to suggest that because violence and crime was happening at some of these events, the political speech they represented might not be worth protecting.