Al's remark is recorded by video. He was clearly taking credit "I took the initiative in creating the Internet" for something. He had a perfect opportunity to respond to criticism and explain what he really meant in his so-called debate with Bill Bradley (it was an Al Gore promotion, not a real debate), which I heard. Bradley said that Al was making a joke when he said he created the internet. Al allowed that to stand. _His_ response to the uproar was to joke about it. The complicated rebuttal provided above (and in Wikipedia) given by people who are not Al wasn't formed until later.
In sum, Al was trying to take credit for creating something he only supported after the creation. Politicians do this all the time. To my mind, it showed how unacquainted he was with the internet. He didn't realize how important it is.
By the way, I'm NOT a Republican, and I support some ideas Al supports, but I'm not going to excuse him of that stupidity.