I guess it is an apology because he used the word "sorry". (Document: Al Franken's acceptance speech).
...It kills me that things I said and wrote sent a message to some of my friends in this room and people in this state that they can’t count on me to be a champion for women, a champion for ALL Minnesotans, in this campaign and in the Senate.
I’m sorry for that....
[He's smiling and thinking, "I just apologized for my sense of humor. What a joke!"]