Why do women treat men with contempt except where they have a good reason not to?

It is in their nature , and has been reinforced and underpinned by feminist and " media " anti-male brainwashing

I treat all good men and women with respect. That’s how I was raised. Everyone gets a fair chance to start with. I treat those who make up unsupported sexist generalisations or those who actively enjoy wallowing in self- pity, a little differently. With distain, if not disrespect. It’s the same for men or women like that.

If someone finds that a large group of people are disrespectful to them when there’s no good reason, they’d have to wonder why. They might need to work on developing a more positive, and friendly personality.