There may be some cases--if a person is on the edge of being eligible for SNAP, or for SSDI for a dependent adult in their houshold, where getting a raise might actually make them poorer. It's wrong to say people do this because they're too stupid to know about marginal tax rates.
My state fixed this so the marginal rate was never over 100%, but there is a rather wide range where the marginal rate is about 75%. For every dollar you earn, you keep 25¢, and are paying in 75¢ in the form of getting fewer refundable tax credits, food stamps, energy bill assistance, and so on. (If I include the energy bill assistance, the marginal rate is 85% in a few bands.)
Which is how some parts of US taxation works, but not other parts. You seem to be in one part, and unaware of the rest.
(And is a mix of taxation and other "eligibility" issues, with poorly advertised massive cliffs here and there for extra helpfulness).