(It was amusing reading the progressively-narrower posts in this thread....)
I'm stilling willing to believe Ellison was being stupid, and wasn't necessarily aware at the time that what he was doing was going to hurt anyone.
Let's assume that what you're willing to believe is true, that the act in question was an honest mistake. Then let's examine the apology. It starts out very strongly, if it's not over-the-top, it's pretty close to the top.
Then the cracks start to appear. 'I've always been like this, and I've been classy about it.' In other words, he's moved away from 'I did the wrong thing' and is now attempting 'How could you possibly be angry with a charming rogue like me?'
Then the cracks get worse, the last paragraph is a not-thinly-veiled statement that he is being criticised due to 'political correctness'. He's turning on his critics and attacking them.
This is not the behaviour of someone who has accepted responsibility for doing something bad - this is the behaviour of someone who is trying to find the right words to make the critics shut up.