There were multiple ways to qualify for Medicaid and some of them are purely based on poverty with no disability or medical issues. Those cases needed the carefully documented income, bank accounts, retirement funds, etc. It's a bad system in many ways in and of itself, but at a high level they do need some way to confirm that Elon Musk isn't applying for Medicaid just for shits and giggles.
The other qualifiers for Medicaid are medical issues that are detached from income.
The frustration of it all is that there is a single form and while you'd hope there'd be a 'skip this section if you do not qualify based on income' there isn't, and you can end up trying to pull together every financial document you have.
( It can be worth a try to attach a W-2 so they have something and stopping there. They can contact you if they need more )