One more time...a little slower this time ......the...."joke"...is...on...the...people...that...voted...for...him
The Joker was unpredictable. Everyone's been saying Obama's socialist since long before he was even elected. So how does him turning out to be socialist = anarchy or unpredictable? The joke can't be on the people that voted for him because most people that voted for him either don't and never will admit to him being socialist, or don't care.
Predictable =/= the Joker. Therefore the picture is using the Joker just for his namesake? I don't find that to be very clever.