What Does the ADL Do?

There has been a lot of commentary about the Anti-Defamation League's decision to oppose the proposed mosque near Ground Zero. One thing that I found weird was, in the ADL's statement about the proposed mosque, the tagline:

The Anti-Defamation League, founded in 1913, is the world's leading organization fighting anti-Semitism through programs and services that counteract hatred, prejudice and bigotry.

So, by preventing Muslims (not al Qaeda terrorists, but American Muslims) from building a mosque, they are counteracting "hatred, prejudice and bigotry", all in pursuit of the goal of "fighting anti-Semitism". The only way this makes any sense is if you assume that the mosque itself will teach hatred, prejudice and bigotry. I have not seen any convincing evidence that this would be the case.