No problem with your post's tone and it's well-argued. But I do think you misunderstand the quantum world - although my understanding is almost certainly not right either. But I hope it's "more right" without being too rude about that. After all, I have studied it for longer!
Anyway, particles don't really act differently when being observed. It is just that the nature of observation is different in a quantum sense from how you would think of it classically. One analogy that I saw early on was the difference between the audience at a cinema and that at a theatre. In a cinema you are bound to watch impassively, but the theatregoers can actively interfere with the performance. But the underlying nature of the performance doesn't really change if you start heckling, even if events afterwards proceed differently.
It's not a perfect analogy of course, but then nothing ever is. Anyway.
Returning to the cat in the box problem, bear in mind that the cat itself is certainly capable of deciding whether it is alive or dead, so for the cat at least it is one or the other. For the man outside the box, he doesn't know until he opens the box and therefore it's one or the other, indeed a superposition of the two. Furthermore, this remains a thought experiment and one can simply invoke the idea of "classical limit" - that is, that this experiment makes sense only if you did it on quantum systems, which the cat is just not. So common sense at cat-scale prevails.
What this means in practice is that you can extrapolate upwards from Quantum mechanics to "common-sense" Newton's mechanics, but not the other way. The classical world and common sense is in some sense a subset of QM, but QM is the underlying truth (but not the end of the story!). Anyway, if common sense goes against a QM solution then it is certainly common sense that needs to change, at least when trying to understand the world more fully.