I agree with MarcherLady, that men have just been socialized to discount and minimize women’s thoughts, experiences and opinions.
It's not just men. It's all of society, women included. Women are exposed to the same toxic idea that men's thoughts and opinions are more trustworthy than a women's. We are all more likely to believe a man over a woman because of what society has taught all of us from birth. We are also more likely to believe a white person over a person of color.
This idea and how it influences us is very subconscious. And of course, the penetrance of the idea is variable. On average, the penetrance is less in women, because we have personal examples of being impacted by it, and thus recognizing the idea as crap. But there are still plenty of women who have drunk the kool-aid, just like men.
https://www.youtube.com/watch?v=flIM3AUyQ3A (the panel of republican women defending K)
The underlying idea is this: "Men are better than women". And this idea is repeated over and over in all of society until you just internalize it as at least somewhat true. I'll give you several examples of where you might see it.
Entertainment is full of stories in which women are portrayed as unreliable, or too emotional. And so many stories are about men, and from a man's perspective. The implicit message is that men and men's lives are more important.
On TV: look at news shows. And notice how often a woman gets interrupted. When she does, she usually stops talking, and waits until she gets a chance to speak again. Men are interrupted less frequently, and when they are, they usually pick up their volume and keep speaking. The implicit message is that men's voices are more important.
In real life: pink and purple are girl's colors. Blue is for boys. If a boy likes pink or purple, it's okay, up to a certain age, usually when they start school, but then they have to stop using it. On the other hand, if a girl likes blue, she can use it her entire life. She's never told to stop using it. The implicit message here is that boys/men are better than girls/women. If a girl wants to be or do something coded as male, that's okay, because she is improving herself. But for a boy to want to do or be something coded as female, that's a step in the wrong direction, and must be corrected.
Sure, there are exceptions to all these examples, like eddys in a stream, momentarily moving the water upstream. But the overall course, is water moves downstream. And we are all exposed to the message that men are better than women in so many tiny ways over our whole lives.
Society spreads the message, and society is made up of all of us. Society won't change until most of us change. And the first step in that change is knowledge that the problem exists.