The ACLU did argue for the right of neo-Nazis to march in Skokie Illinois in 1978. However, they argued for their right to express their thoughts and ideology, not lie as to the facts. Current Constitutional standards regarding free-speech are based on the statements of Justice Oliver Wendell Holmes (originally in his dissent in the Debs decision and later amplified in his majority opinion in Schenck), who believed that the right to free speech has its limits. It is not absolute. As he stated in Schenck, writing for an unanimous Court, “The most stringent protection of free speech would not protect a man falsely shouting fire in a theatre and causing panic… The question in every case is whether the words used are used in such circumstances and are of such a nature, as to create a clear and present danger that they will bring about the substantive evils that Congress has the right to prevent.”
To use an analogy, It is one thing to claim that whites are superior to blacks as a belief. While repugnant, such ideas are protected speech. It is something else to propound lies as facts in an attempt to prove it. That is not protected. When such lies are used to take away the rights of blacks or to encourage violence, that is not protected speech. A line has been crossed. The same applies to people crying that the trans community is mutilating children. This is a lie which is not protected speech. The consequences are already being felt. There have been violent confrontations between people with Christian nationalist leanings, and those who are members of the LGBTQ community. Oppressive laws are being passed to take away the rights of such individuals. This speech is not without consequences. Therefore, it is not protected.
Russian interference in the 2016 election promoting lies, whether it was the deciding factor in Trump’s victory or not, is not protected speech. It clearly had an impact, even if it was not dispositive. (I do not disagree that a major cause of Hillary Clinton’s defeat was due to strategic missteps, such as calling Trump supporters deplorable. This is not a way to win friends and positively influence the undecided . It was a self-destructive comment.) But there is a difference between those on the left who are intolerant of absolute lies, and those who merely do not want to hear unpopular opinions. The latter are protected. The former are not. Unfortunately the examples you used related more to falsehoods than opinions. That is the distinction I was trying to draw.
There is a reason that there are common law principles creating liability for defamation. Saying untrue things about others can have debilitating real world consequences. Just ask Dominion Voting Systems. They now have the benefit of 800 million reasons as to why the intentional lies propagated by Fox News are not protected speech.
In my experience, most on the left are willing to engage with people who hold beliefs born out of ignorance or bad information. We encourage those kinds of discussions. That is not to be afraid of free speech because of the lies propagated by the right. It is actually to be welcoming of open and fair debate. We both agree that the right engages in far more onerous attempts to suppress speech than the left. But let’s not overdo it in accusing the left of more bad behavior than it is actually guilty of merely because it draws the line at not tolerating lies and disinformation that have no basis in reality or truth.