Right now neither MC nor TGIB are dating anyone else, so I haven't had to deal with this exact issue, but it has come up in regards to family members and close friends, but in situations where I'd be seen as more the "trash talker". Both MC and TGIB have family members and close friends that I don't have high opinions of. I'm honest with them about it, including my reasons, but then I leave it alone. They can't choose their family members (and in the case of friends they made the choice 10 to 20 years ago, so it's not up for debate now!), nor can they change them, and it's not up to me to decide whether or not they try to maintain a relationship with this person. It will sometimes come up again when THEY are venting about the person in question, and sometimes they will feel the need to defend the person against my opinion. *shrug* It's just my opinion, and while in some cases I wish they'd see something the way I do, I can only make choices for myself. If it were a new friend or relationship, though, I'll bet there'd be a LOT more debate on my part around the question of, "Why, exactly, do you want this person in your life??"
Conversely, I have no doubt that some of their family and friends are confused about why they each chose a relationship with me. I agree that name calling is immature and usually unnecessary but for me the relevant question is, does the person who dislikes me respect my relationship with their friend/family member? Or are they trying to undermine it and get us to break up? That matters WAY more to me than if someone thinks I'm a bitch. Cause frankly, a lot of people think I'm a bitch, with cause!
Pan Female, Hinge in a V between my mono (straight) husband, Monochrome and my poly (pan) partner, ThatGuyInBlack