Why do some people view the ACLU as a left-wing organization?

None of the people I've spoken to about it could cite any actual examples of such left-wingity, other than vague ertion about 'getting god outta the schools'. The ACLU seems to stand up for everybody's rights, left or right. Also, they don't have any actual power to do anything; they're lawyers. All they can do is bring lawsuits like any other person can. They ask courts to clarify laws and make rulings that decide whether people have certain rights under the law, laws they didn't write. I don't understand the hate. I don't always like who they represent, but that just reinforces their neutrality...