My high school teacher did explain many of the things commenters are complaining they were never taught. Gave bits of history, talked about summing very small pieces, apologies to speed and acceleration, etc, etc.

And calculus was still very difficult to understand and warp your head around. And as a high schooler, the history seemed like a sidetrack.

I guess my point is, this stuff is difficult no matter how you slice it and it needs time, reflection and retelling in order to make sense.