Is the last paragraph of John's letter written tongue in cheek, or is he serious? What does he mean by "the Despotism of the Petticoat" (para. 19) ? How do you interpret this ending?

In "Despotism of the petticoat," John Adams meant that women were using the influence of their womanhood. Because of the power held by women, Adams argued that they need not have suffrage and equality power. Women interpreted that without having a man, they were better off. It would have created inequality between both sexes because men may need to rely on a woman for certain needs.