It was actually necessary honestly to show the divide between men and women in society.
You've got to understand that Princess Diana grew up with the mentality of thinking how men are and she grew up on a woman-only island or community where she had limited experiences with men so when she gets in the real world Steve beep up by acting like the image that Diana had gauged into her brain.
Luckily for her Steve actually wised up in the hospital and finally showed how decent of a person most men are and that they portray the traits that she thought women were about.
If you grew up in a women-only community where you were so strong and independent you would have this mentality too so don't be a sexist about this thing.
It's definitely not a feminist ideal view of the world it's showing how lack of communication with the other sex will hinder your views of that sex if you don't have a positive experience with that sex in your life.

That kind of why this movie sucks. Its old feminist propaganda.

This is true. My favourite thing was during Justice League: The New Frontier after the Centre unleashed his dinosaurs and WW was just flying in the sky screaming at the men to fight until the end as they were getting eaten and killed, sums up that disgusting hate movement perfectly.