2017: the ACLU defends Milo Yiannopoulos' right to advertise his new book. They file an amicus brief in the Supreme Court supporting a Tea Party supporter challenging a ban on wearing political insignia at polling places.

2018: the ACLU supports the NRA's First Amendment challenge to Governor Cuomo's attempt to convince NY financial institutions not to do business with the NRA.

2019: they defended a conservative student magazine which was denied funding by UCSD.

2020: they filed a brief supporting antisemitic protestors picketing a synagogue on the Sabbath. They also supported a Catholic school's religious right to make religious-based choices in hiring and firing teachers.

I'm just quoting the fruits of five minutes of research here, so I won't go on (but there's more). Is it possible that you're reacting to the radical conservative stereotyping of the ACLU rather than the actual actions of the organization?