Tax forms have the instructions on them.

If they're smarter than their parents, they will be taught how to learn it on their own, bare minimum. If they're equal in intelligence or dumber than their parents, they can't learn it anyway right?

Since wages haven't kept up with inflation, both parents now need full-time jobs, and most need an hour or two to mentally separate from work before thinking about teaching their kids things they asked for help with. It would take an amazing human to get done with their stressful 8 hours and immediately think on the way home 'hey, I want to try to talk my kid into learning to do taxes tonight, and for the next few nights!' K-12 is glorified government babysitting at this point, a way to try to keep kids from getting into trouble. But read my other comment, most of this stuff is taught in most American schools already. Bitching before doing your own self-reteaching is just something that comes naturally for people and this bitching point has become a meme (looks up oh, literally I guess, hah)