Have you tried learning something like algebraic topology, or representation theory, or anything that actually uses it (and for which it’s truly indispensable)?

Have you tried learning something like algebraic topology, or representation theory, or anything that actually uses it (and for which it’s truly indispensable)? I think if you do, you’ll discover quickly why category theory is so nice — and useful! Its origins aren’t in staring at a blank sheet of paper and trying to come up with needlessly complicated notations and idea; it comes only after centuries of observation and gradual pattern recognition. Conversely: if you don’t, I don’t think you’ll ever get it. At least not without much difficulty. It’s a bit like set theory: basically everyone uses it because it’s such a useful paradigm; hardly anyone studies it for its own sake. Those who do can tell you ‘theorems’ of set theory, and those who do the same for category theory can tell you ‘theorems’ of category theory. The rest of us use it as a convenient (and mind-expanding) language. By the way, you shouldn’t consider it to be some kind of ontological theory (or even foundation) for mathematics. It makes no attempt to tell us what there is, or even particularly what is true; it gives us a way of simultaneously generalising thousands of definitions and facts, allowing us to see commonalities between a priori only distantly related concepts and therefore further generalisations more easily.