I'll start by saying I'm not the one that downvoted your question. However, now that I've read it I don't like it. I'm not sure I'd go as far as downvoting but I wouldn't upvote it either.
First off everything you've written and commented on since coming here is very long-winded without saying anything. The answer in question is no different.
The question is:
What would be the best way for people like me to learn the reasons behind the intuitive decisions I make?
You didn't answer that. You instead give some very abstract commentary about a variety of things. For example:
In the same way that you "intuitively" use a specific font, or icon, or section, or line width in an area of your design, I'm using spacing and font weight/size to present your eyes with a balanced set of visual content that you will feel comfortable with interpreting as I want you to, rather than skimming past it.
Looking past the assumption that anyone finds your visual scheme appealing (I for one do not), the OP has already stated he understands balance and spacing. He wants to know more about the underlying principles of how these things work. You didn't say
"Formal balance occurs when equal, or very similar, elements are placed on opposite sides of a central axis. The axis can be vertical or horizontal. It may be a real part of the design or it may be an imaginary line."
All you said was, "HERE LOOK AT ME I DID BALANCE."
It's not useful at all, and being so long to read means its also a waste of time.
The website tells me whether I'm correct. Like a game maybe. -- The website tells me the reason why it's correct and offers a link to read the theoretical background. (Beginner mode) -- In the next step I have to give the reason as well. (next level)
He points out these features, suggesting a game or website that does these things. My first thought, "Oh my, he's already found it. It's called Graphic Design SE. Let's start him out on level 1, by explaining the question that he asked in the title. @DA01