Doesn't that constitute an immediate refutation of the "instant irresistible motivation" strategy? In other words, it takes willpower to remove the negative motivation, or to employ the desktop strategy, for example...

As I've pointed out many times, I chose desk cleaning as an example because (among other reasons) it's something that most people don't have a negative motivation in effect for. That is, their main objective in doing the process in the video is not to fix the terrible emergency of an unclean desk. Thus, it works nicely.

Another thing that happens, is that sometimes people do it while not expecting it to work... which pretty clearly indicates that their motive for trying it was not to solve whatever problem they were (ostensibly) trying to solve by using it.

In any case, the technique does use willpower... sort of.

At the end of it, you are instructed to use willpower to try NOT to do what you're motivating yourself to do, and to hold off as long as you can, before your willpower fails and you actually do the task. ;-)

So, IIM is actually premised on the assumption that your willpower will fail... and the marketing strategy behind it is premised on the assumption that if you have a bunch of negative motivations that are motivating you to use it in the first place, you'll still need help removing them.