Humans are horrible in general. It’s hard finding your tribe, meaning at least good friends and a community; and it’s even harder finding a good partner. Women were raised to take care of others, to be nurturing - after all, it’s in our nature. Men aren’t always this way. According to what I’ve been observing since early age is, unfortunately most people aren’t good candidates for happy long-term relationships, and there are possibly even less good candidates among men.
Long story short, finding good men is hard because they are extremely rare. And those who believe they are good are often wrong.