I think the advertised community experiences are not real community experiences. I think that is why they aren't in the server browser. They are usually made by "battlefieldofficial" and usually have strange gameplay compromises that go against the supposed stated server objective. For example, a "hardcore" mode with non-hardcore health, and an "infantry-only" mode with tanks in some maps. They are oddly "highlighted" as community experiences on #FNB nights, even though they aren't made by the community and are the same experiences highlighted over and over again since the game was released.