Complete idiots.
I don't pretend to any special inside info about it, but I know how operational planning cycles work in both conventional and unconventional warfare, and I know how long it takes for asymmetric partisans/terrorists to formulate, set up, and bring a complex covert plan to fruition without it being detected by the power against which it is being directed. It's a certainty that the pieces of the plot were in motion long before the election, and once initiated, there was no going back.
Osama couldn't have given a rat's ass for the difference between Gore and W. He would've just seen Gore as a cat's-paw of Clinton, against whom he had plenty of motivation to move after all the Tomahawks the Horn Dog shot at his Afghan camp - and Osama would have likely been correct in that assessment, he always had a much better intelligence appreciation of Clinton's limits of action than Clinton did of Osama's.
Clinton was an incompetent fool in dealing with Osama, but Gore would have made Clinton look like Alexander the Great by comparison.