Because any disagreement with a feminist over patriarchy theory usually starts with accusations that the dissenter doesn't understand what patriarchy is and/or is deliberately misdefining patriarchy and/or privilege to support their argument, and generally ends with the feminist ordering the dissenter to come back when they've "educated themselves," let me demonstrate my working understanding of patriarchy as put forth by feminism. We're talking institutional discrimination, not individual; things like executive glass ceilings, the wage gap, and abortion rights. Systemic stuff. It's not a conscious, intentional conspiracy by men to keep the wimmins down, but a system of male domination and female subordination largely benefiting men and limiting and/or disadvantaging women. I invite corrections in the comments.
The elephant in the room is the question of why, if women are so strong, smart, capable, competent, and all around equal to men, then how have they been oppressed by men since the dawn of time? Other groups commonly accepted to face institutional discrimination are overwhelmingly outnumbered. For example, blacks are 13% of the population in the United States. Jews are 2%. Gays are 1.8-10%, depending on who you ask, and transgenders just 0.3%. But women are roughly half the population, and always have been. So either women are so weak and fragile and incompetent that they took literally thousands of years to rise up against their oppressors and even begin to finally demand equality, or, the idea that women are oppressed is a new one that is being applied retroactively.