Why does everyone call their ex partner a narcissist when it's just not true?

I have given a lot of relationship advice to friends or even random strangers online. Almost all women led me to believe their ex boyfriend was a narc but once I got to read all the text messages or even talk with the ex boyfriend, I could tell it was a lie. And almost all men who said they were perfect boyfriend were horrible boyfriends. Got lazy stopped telling girlfriend they loved them played to many video games etc no Date nights.
Why does everyone call their ex partner a narcissist when it's just not true?
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