Would you be friends or talk to someone who talks badly about your parents?

If they have a good reason to, sure. Unconditional love is a really strange concept, especially for people you didn't choose to become part of your life. If people harm you in any way, you are allowed to speak up, especially if they are the ones who forced you into [i]their[/i] life.

And if others agree, they are welcome to speak up about my parents too.