Funniest shit is that this is basically how IT was eventually defeated. By being ridiculed and laughed at.
Well, that and a preteen orgy ("no, it was a train!", yes I know).
That's why he could only watch the disrespect: The very act robbed him of the power he weilded. In that moment, he was nothing more powerful than a human stuck in a sewer, watching a child literally shit on the thought of playing with him.
Thank you for succinctly summing up why this scene was powerful and not just smut for the heck of it. A lot of people have issues with that scene but this is the exact reason it's in there.
Some of mine float. Others don't. One time I shit for 30 minutes. Really crapped it out. Then I stand up, and the bowl is clean!!! I go to wipe, and there's no poo!!! What the hell was I expelling for 30 minutes???!!!