I closed the question because it really doesn't have anything to do with the Raspberry Pi, but I can see now how this might not be obvious. I had hoped my comment would clarify this.1 Let me explain:
it has to do with Raspberry Pi GPIO and connected hardware
Tangentially, but you rule out any issue with this when you point out that
when I "cat /sys/class/gpio/gpio24/value" I get a "1" when theres no motion, and "0" when theres motion. And when I do "cat /sys/class/gpio/gpio25/value", I get a "1" when the cover on the motion detector is closed, and "0" when the cover is open.
So there is no question of a GPIO problem; everything is working exactly the way it is supposed to. The crux of the issue is you are trying to use inotify to monitor a sysfs "file". I've reopened the question and turned my comment into an answer going into more detail.
Considering the fact that this is probably a more significant issue on the Raspberry Pi than for Linux users generally, I made the wrong call with this and apologize. My thought at the time, since I knew there is no solution to this problem, was to explain briefly why what you were trying to do can't work in a comment and just close the question, rather than migrating it to U&L.
1. To which I now notice you replied shortly after, but since the comment was not directed at me, I was not aware of this. If you want the attention of someone on a Stack Exchange site, make sure you include, e.g.,
@goldilocks in the comment. This will only work if that person has already posted a comment in the same thread. The interface provides auto-completion for this after you type @ and the first few characters.