You definitely have a point, and there are definitely women like the one you described in the world. Men 100% deserve to be treated with equality and respect. I'm sorry that you had that experience with your former partner. It's a garbage, disrespectful move from someone who is supposed to have your back.
But your point does ignore the fact that a majority of women have been raised by parents and by society to be subservient to men. The person who posted this originally wanted to know why women aren't taught how to treat men, but the fact is that we are. Constantly. Whether we want to be taught or not. Most of us have learned to do this so deeply that it's second nature. Most of us don't even remember learning it because that's just the way that it is.
This is for a wide variety of reasons, but most of it boils down to men having control over the world for thousands of years and women trying to find the best way to survive and occasionally excel in a world made for and by men. Remember that we used to be (and often still are) considered property. It's taken a really long time to get as far as we (women) have. My sex has only been able to vote in my country for 100 years. That's not a lot of time to make major changes in public perception and major societal shifts. We've grown a lot, but these shifts come with growing pains.
If we lived in a world where women have to be taught how to treat a male partner well, that means that society isn't doing the teaching anymore, and while yes, women should treat men with equivalent respect, it's still a huge improvement societally that women don't develop ingrained subservience. The woman that you previously dated sounds like part of those growing pains. Some people are always going to take things too far because the line had not previously been defined (even though the golden rule should be pretty common sense).
Conversely, men often have to be taught this because society doesn't do the teaching. Society is cool with men following the status quo.
Does this give a woman a solid reason to treat another human like trash, no matter their gender? No. This is the big reason why I think feminism is so important. People hear that term and think it means pro-women only, but what it really means is equality for all genders. Full equality should be the goal even if it ends up hurting women a little. For example, one of the few privileges women have that men don't have is in the courtroom. Women tend to have better outcomes because of biases about our weakness and innocence. Feminism would be working to dismantle something like that even if it gives women an advantage.
Equality is important, but understanding women's historical growth and struggles is important, too. Women have been taught ad nauseum how to treat men well, but some women are going to make different choices. At the end of the day, I agree with you. I just want people to remember how hard the struggle was for women to get here, understand how far we still have to go to gain real equality, and respect the societal pressures that we deal with every day.
I've never seen a truer post.