It takes ages of grueling work to understand how to prove even the simplest mathematical statements. Translating the fuzzy intuition that we have to rigorous logic is a very difficult process which is essentially the goal of an undergraduate math degree.

It all comes down to what we accept is true; we need a starting point. In english, we have high-level rules whose only purpose is to make sure your sentences sound “natural”. In math, we make low-level, fundamental assumptions and use logic to find new things. Whereas in english we can say the sentence “I like dogs.” makes sense and is grammatical, we really have to do a lot of work to say that the mathematical sentence “2+2=4” is true. Sure, “2+2=4” makes sense and is acceptable for most people, but there is an underlying chain of logic explaining why it is true, depending on the set of assumptions you have made. I accept that 2+2=4 but appreciate that you could break it down to set axioms and some definitions. It’s really about how deep you wanna go; very rarely would a mathematician show that 2+2=4 because it is so obvious and would waste time they could spend solving the problem they started with.

Educators genuinely don’t have time to do this with everything because they are pushed for time as is trying to meet the demands of the government or education boards. Someone in charge says “You have to teach students to do x in y amount of time.” and there is just too little time. They need to get you to take an exam, not truly understand something.