My employer's yammer isn't that bad tbh. Lots of different sub-groups, eg there's one where people just post pictures of their dogs, and others about special interests relevant to the work we do etc. Most of the groups seem to get used as a news comment area where someone will like a news story or maybe a scientific paper and people will chime in (often seem to be a small number of committed yammerers with strong opinions though).
General announcements and policies etc are posted in the intranet though, not Yammer.
In theory I can see yammer being used as a tool for fostering communication between people interested in a topic across the organisation, or getting a sense of general sentiment about an announcement across the organisation maybe. In practice it is basically a work-Facebook used by a small minority and I'm not sure what value the organisation really gets from having it (compared to the risk of a toxic atmosphere developing, which Tbf I think may have happened in some groups based on a post about that happening) . I've not encountered any behaviour as insufferable as that described by OP though.
General announcements and policies etc are posted in the intranet though, not Yammer.
In theory I can see yammer being used as a tool for fostering communication between people interested in a topic across the organisation, or getting a sense of general sentiment about an announcement across the organisation maybe. In practice it is basically a work-Facebook used by a small minority and I'm not sure what value the organisation really gets from having it (compared to the risk of a toxic atmosphere developing, which Tbf I think may have happened in some groups based on a post about that happening) . I've not encountered any behaviour as insufferable as that described by OP though.