SOME Aspies... that's the key. Some people on the spectrum are very very good with maths, others aren't, for verious reasions (with AS it's often a combination with nonverbal learning disorder, or with Dyscalculia, plus verbal comprehension problems makes learning maths the conventional way difficult too).
I dont blame you. I felt the same way when my art teachers tried to break me of drawing things exactly like they should be instead of sketching them out in big ovals first. I felt that as long as the result was an accurate drawing, why try to make me do it a different way that seemed too hard and less efficient.
I guess the teachers were trying to teach us a particular method rather than answers was the point. I nearly failed Algebra in 9th grade. But in college I got an A in it, because they just gave you some slides to study by yourself at your own pace. Doing it alone made a huge difference for me.
I can relate to that, never liking to draw the ovals first but just doing things freehand. Luckily my art teachers weren't sticklers for drawing the ovals but we did have a silly idea once for the kids in the class to mark each other's work.
Well, the less talented and jealous ones had a field day in picking fault with other's work and I marked all the pictures reasonably highly as they all had merit in their own way.
But when it comes to proof-based maths in the uni, I struggle with it (the lower-level proofs in high-school were absolutely no problem to me...)
Well, depends on how you define it...
Most annoying thing about math in general is that it seems to have become common practice to drill stupid shortcuts into our head so that we can "do" the math and then only later reveal that those shortcuts we learned are really just an easy way to do something that while more complex, is much easier to understand than some abstract "shortcut".
I also think the problem is that "shortcuts" are abstract and it is hard to visualize an abstract idea, which for me is rough because most everything in my head is visualized. So, I've always worked to learn the base concepts or rules involved in math and from there I can build up my pieces to solving most problems. This can be tricky though as not every teacher will understand the basis for the "shortcuts" that they are teaching.
The memorization problem was luckily solved by a graphic calculator *whew*. Or by a cool website called quickmath.com.
It would have helped me if the teachers went through step by step and a bit more slowly so that I would understand. But then they had a certain amount of work to get through and I probably shouldn't have been doing the advanced maths in the first place.
However, because I got good marks in all my other subjects except for physical education and did well in maths in primary school, it was considered I would have no issues with secondary maths, especially senior maths.
I'm still good with figures, but anything abstract is a struggle because I can't see how it is relevant to real life.
My mother was a math teacher, so she explained to me that she had to see every step to make sure those were right. I think it was like each step, including the answer was the same weight for a grade.
Some things are just better learned by rote, I think. I also believe that doing stuff like big ovals in art class stifles creativity for some of the students.
Now that I'm a teacher, I finally understand what they were trying to do. I tell my driving students that I am drilling them on doing things the exact proper way while we are going a slow speed so they will get good at those skills before they get to high speed when they'll really need them.  I suppose the math (and art?) teachers felt like our natural way wouldn't work for a much harder challenge down the road.  Their job was to teach not the answer but how to find the answer.  It still bugs me though, in my own little stubborn way. :-)
.Later on, I "turned my back" to maths and studied the Law (doctorate there).
My stepdaughter is a maths student now and now I'm at a loss when she starts talking about it.
I wouldn't have minded being in trouble with my parents if it resulted in getting extra assistance, as I think I could have "got" the concepts with some one to one tutoring. Arithmetic is still one of my stronger points so I wasn't bad at all types of mathematics.