Why did the ACLU defend Rush Limbaugh? Why do they defend conservatives and/or conservative's rights?

The ACLU doesn't discriminate(no matter what the Right wing in this country tells you) The ACLU has defended the Westboro Baptist Churchs' right to protest outside of soldiers funerals(a truly disgusting thing to do) because even the people of the Westboro Baptist Church have the right to freedom of speech.