I've seen this with guys. And I've seen loyalty with women.
I've also seen people who are there for the good moments but not for the bad ones.
And then you have the people who only came to you when they need help.
Good friends are difficult to find and you need to cultivate them. But they are there if you pay attention. What is clear is that if you want good friends, you need to start by being a good friend yourself. Thinking the worse of others doesn't help. Neither to forgive everything.
I hope you find the friends you want.