The ACLU has defended the rights of neo-nazis and pedophiles. They defend people that no one wants to defend including democrats.
"There is a healthy and an unhealthy love of animals: and the nearest definition of the difference is that the unhealthy love of animals is serious. I am quite prepared to love a rhinoceros, with reasonable precautions: he is, doubtless, a delightful father to the young rhinoceroses. But I will not promise not to laugh at a rhinoceros. . . . I will not worship an animal. That is, I will not take an animal quite seriously: and I know why. Wherever there is Animal Worship there is Human Sacrifice. That is, both symbolically and literally, a real truth of historical experience."
http://www.nationalreview.com/corner/421961/wherever-there-a...
https://www.aclu.org/blog/ag-gag-not-just-about-animal-welfa...
https://www.washingtonpost.com/news/the-fix/wp/2015/06/19/a-...
Which is something that can be found with a straightforward Google search, I must add, so the sheer number of comments here that are asking this question makes me conclude that most of you doing that believe the question to be rhetorical. As in, you assume that ACLU does no such thing, because "everybody knows that".
Well, "everybody" is wrong.