Unfunny "joke" of the day

Rope + Tree + ACLU Lawyer = Pinata

From Stop the ACLU (via Orcinus)

Here's the disclaimer they ran after a website pointed out that STACLU had photoshopped a picture of Albert Einstein advocating the murder of members of the ACLU:

"For those who are too stupid to understand, the below picture is satire. It is a joke. We do not actually advocate murder in any way here at STACLU."

Could someone explain to me what the satire of Albert Einstein writing an equation on a blackboard that has as its solution the death of ACLU lawyers is? Sorry to say, I don't see it. What I do see, is a "joke" which only works if the audience hates the target.

Really, if someone said

tree + rope + nigger = pinata

Would you think that's funny? I expect some southern racist in the 1920's would think that's a good joke, and might try and defend it on the same grounds.

But hate is not a joke. And its not funny.