Much of that is because they have many chapters, and the parent org isn't in control of all the chapters, and the chapters are loaded with left leaning partisans. But the Parent Union isn't immune to partisan biases, and the excuse doesn't matter as much as the outcome.
❝ The smallest minority on earth is the individual. Those who deny individual rights cannot claim to be defenders of minorities. ❞
The ACLU once firmly believed that and were civil libertarians, but they've drifted away on many issues, to being more partisans and libertarians,.
The ACLU officially no longer supports liberty on the following issues:
- The ACLU supports affirmative action -- which means they no longer defend non-minority individuals against state controlled quotas and preferences. You can't support social justice without opposing individual liberty. (The irony is we're all minorities, as every white European male group is quite distinct from the rest, and thus smaller than the groups that are usually attacking them).
- Birth control and abortion - they don't believe in the rights of fully viable full-term fetus's until they've travelled through the magic birth canal to instill humanity on them. So they're not quite NARAL, but they're almost indistinguishable on many issues.
- Gun rights – they don't believe the Second Amendment protects and individuals right, despite it saying so in the Constitution, the letters of the Founders, by most Historians and Linguists, and multiple Supreme Court cases. (They do oppose a registry but that's under privacy grounds, not the right to self defense or Constitutional originalism).
- The ACLU decides that free speech doesn't apply to gun-owners who exercise their constitutional rights. 
- The ACLU doesn't care about 4th, 5th or 6th Amendments, or attourney-client privilege, when it is a raid against Trump's lawyer (Michael Cohen). 
- Then they went on to decide that free speech doesn't apply to hate speech, or any speech that isn't liberal/progressive enough. 
- Voting rights – they're against the integrity of our elections (VoterID), they're for criminals and illegals being able to vote (or seem to come down on that side).
They're still almost Civil Libertarians in the following issues:
- Campaign funding - they mildly support Citizens United, which is a good thing, while also supporting public campaign financing: socialized campaigns, which are antithetical to individual liberty and rights. You can't force people to donate to the opposing candidates to make things fair, without taking away their individual rights.
- Child pornography - they oppose it (in theory), while supporting the rights of people to have it. This one is a grey area for me, as having it requires that a child was exploited in the first place. So while I favor liberty, this is like allowing people to have lamps made from other humans: the only way to have it, is illegal, then we should probably agree to outlaw it entirely and not split hairs.
- Criminal law reform – The ACLU seeks to lower punishments at about ever level.
- Death penalty – The ACLU is opposed to the death penalty in all circumstances -- in other words, individuals should not be able to seek justice if it collides with ACLU religion.
- Human rights - they are spotty in some areas of children's rights, immigrants rights, gay rights, crossing lines where a country has no rights to defend its border, or touching issues where individuals can't discriminate against others (something that might sound good, but is not civil libertarianism).
- Racial issues – The ACLU's combats racial discrimination unless it's against White Males (affirmative action). On the flip side, they support free speech on things like allowing the Confederate flag
- Religion -- they're hit and miss. They defend people's religious freedom to an extreme (not always bad). Unless it's someone that says they don't want to make a Gay Wedding cake. They support kids rights to pray in school (mostly). But they seem to occasionally get on the wrong side (at least at the state/local levels) of those that want to opt out of paying for other people's healthcare or abortions.
They're still good in the following issues:
- Free speech – The ACLU supports free speech, including the right to express unpopular ideas, such as flag desecration.
- National security, Privacy and technology - they actually go too far for my tastes on some areas against spying, enhanced interrogation or indefinite detention of enemy non-combatants. But I can respect their civil libertarian position on these things and moral consistency to their charter, even if I think the rules around the ticking time bomb scenario, and observation of foreigners should be a little looser than they do. They get credit for being civil libertarians, even when I'm not as much of one in that area.
I could support them more, if they were consistent, even on issues I disagree with them on. But they decide what liberties are individual liberties and which are only group liberties. They often fight for convicted, seldom for the rights of victims. Thus they take up some causes that I don't like, but agree with them on: defending the KKK's right to protest, as detestable as they are. But then they look away when States are attacking other States or Companies for not having quite the same position on catering gay weddings or how they regulate transgender bathrooms. They put on their crusaders gear to defend Muslims (goodonya), but then leave it at home for Christians being persecuted.
So what the ACLU says here, is that we support only certain kinds of freedom that aligns with their political agenda are worth defending. Preserving the liberties of assholes was kind of their job. Their new job is starting to act more like an inconsistent front for the DNC.
Here's a few examples of the ACLU either fighting against civil liberties, or lying about the cases they took and what they were about. Note, even if you're fighting for a good cause, being a liar makes you a polemic and not a good champion of the cause. ACLU : 12 items
Some of our personal favorite Thanksgiving conversation starters:
💬 "My pronouns are…"
Any douche that starts a Holiday conversation with those, should be thrown out of the house. And anyone that suggests starting conversations with those should not be let in.
In the distant past they used to have some plausible deniability because it was often their local chapters that were fanatics, and their national organization was doing damage control and trying to tamp down the damage they were doing. But since they put Ruth Bader Ginsberg in the Supreme Court, as the least civil libertarian currently sitting there, they've become a mockery of their own name and mission.