Why do we have to learn most of the material in Algebra 2 and on?

What a strange question!

You don't have to...no one can make you!

You can drop out of school.

You can truant.

you can pay no attention.

I am quite sure you hve a heap of other options as well !!

If you do not want to learn maths, you should consider not attending a maths forum...

Just a thought.