They just don't seem to hit the news. They defended a Christian protesting against Wal-Mart's favorable gay policies (which is diametrically opposed to the ACLU's gay rights mission). They defended a Mormon who was being penalized for doing his mission, when the school gave leave for other reasons. They defended a kid who wanted to sing a Christian song in a school talent show. They defended kids who wore anti-abortion shirts to school. And they defended at least two street preachers. This was all within the last few years.
Here the Georgia ACLU threatened the school board if they didn’t pull the word Christmas off the school calendars.
There are simply too many cases like these to defend them.
Unless of course one’s agenda is the same as theirs.