#2 is because "spiraling" is a hot concept in math right now. I don't have a particular opinion on it, but the ideas is that they study several concepts, them move up a level and student the same concepts again. They build on them, but it's like circling around a mountain to get to the top, not going straight up a set of steps. This didn't seem to bother my DD at all though I admit, it drove me a bit batty.
#1 I think you sorta have two complaints here. There ARE a lot of different ways to get to the same end, and different textbook companies pick different ones. Different kids really do learn better from some methods vs others. As a very visual learner, I've always found visual methods, diagrams, etc extremely helpful to me. I haven't seen that particular Khan Academy problem, but that sort of methods could make good sense and really help some kids. Our kids aren't necessarily those kids because they "get it" so quickly through pure logic.
