With a smaller plant you definitely do not want to remove heathy leaves. In general never remove more than 10% of the leaf area at any one time. If the newer leaves are smaller then the spot you have it is definitely too dark.
And to answer your original question, “Why is plant knowledge voodoo?”.
There literally hundreds of thousands of plant species. Each of those species is adapted to different environmental conditions. The requirements the species need are further modified by its interactions with micro-orgsnisms. So the answer to most questions about growing them requires an significant depth of theoretical and practical knowledge on the subject.
A large portion of humans quickly revert to mythology when any topic becomes slightly complicated.
The plant will adapt in time. Monsteras are tough but a bit dramatic at times.
I forgot mine outside when I lived in an area that seldom frosted. It frosted hard (22F). I thought I had lost it. It came back from one little piece of stem.
Just call it the diva it is and let it grow out of it.