It's pointless because if you can't do it, you're not qualified to teach and it's busywork because doing 30 students' 30 first grade math problems takes a lot of time that can be better spent doing things that actually benefit the class.
It sounds like you've had bad teachers, for which I pity you. I had many good ones, as my mother was a teacher and my parents made sure we got a good education, both at home and at school. Perhaps you've only known people who were made to teach subjects they were unqualified to teach. That is sad, then, if you haven't known good teachers.
But that says more about you than teachers in general. You have something against teachers, as I've seen this axe ground before.
It sounds like you've had bad teachers, for which I pity you. I had many good ones, as my mother was a teacher and my parents made sure we got a good education, both at home and at school. Perhaps you've only known people who were made to teach subjects they were unqualified to teach. That is sad, then, if you haven't known good teachers.
But that says more about you than teachers in general. You have something against teachers, as I've seen this axe ground before.