We picked a name for this little squirmy bundle that I am carrying. It's not a secret, we've been sharing it. My feeling is basically that if we've decided, there's no reason not to. If you haven't decided, and you share the names you're thinking about, then you're opening yourself up to feedback. You're basically telling people they are welcome to help you decide. We've decided to name our daughter Lucy. A simple, pretty, straightforward, unfussy name that I've liked for a long time, and absolutely loved paired with Mia. Mia & Lucy. The name itself, however, is not the point of my story.
The thing is, when you share the name you've picked, you aren't looking for feedback. You just aren't. If you really want to avoid all feedback, then you keep the name to yourself until your child is born and named. But that's just isn't how we are! Sharing the name is fun, and I've come to expect that the people I am sharing this piece of information with know the rules. If you aren't pregnant, and are talking hypothetically about baby names, then opine away. That is the time to share whether you like someone's choice. If someone is pregnant, and they're telling you about what names they like, your role is simple: if you like the name, enthuse away. If you don't, pretend you do. The rule doesn't change, no matter who the expecting parents are, no matter what your relationship is to them. You do not have a role in naming their child.
Of course, you can guess from the above that someone strayed from that rule. None other than my Father in Law, B's Dad. Of course, someone whose behavior can bring me quickly (very quickly) to anger. B isn't great at keeping in touch with his family. He speaks to his father monthly, at most. It's not that they aren't close, I think they are, but keeping in touch doesn't occur to them. B and his Dad had their monthly catch up yesterday, and B shared the name we had decided on.
FIL's reaction: "Nah, I don't like it." Very casual, very matter of fact. B's response: "Uh, OK. Well, that's what we decided, so that's what she'll be named..." FIL's response: "[Wife] doesn't like it, either." ... I am, sitting on the couch, just outside of FaceTime range SEETHING. Shaking my head, making SEETHING eyes at B, who is also, visibly upset. FIL tries to change the subject, ask what else is up. B informs him that it's time to make dinner (despite it being 4pm...), and they hang up.