You're right, which is why you can't have one function without its counterpart being strong but unvalued, they are two sides of the same coin, but you can't look at both of them at the same time. You don't keep up with the emotional atmosphere if you evaluate everything that's being said against your own Fi judgments, and you don't act strongly on your Fi judgments if you're trying to maintain some kind of atmosphere. I wouldn't say it's a sheep thing or hive mind, it's more like keeping the energy in the room up and running to a degree that's satisfactory to you, such as... Liking everyone's posts to encourage responses

The problem with discerning is that they are both strong, and the only way you can really tell is by looking at other functions, quadra values or both.