Buzzcook...
Without meaning to sound like a jerk (or, at least, any more like a jerk than I may have, earlier)...
... the OP in the previous thread didn't post a link to the case we were discussing. One thing we do not know, from the info that was provided, is how many police were on the scene. The "group" may have been two officers; we were only told there were officers, not how many; we also don't know ages, genders, and sizes of the officers who were there.
Additionally, we don't know what the original attempt at an arrest was over. If the guy was behaving oddly, and that was the reason for the call, then the officers' reaction might be different than if they were responding to a call of a guy who had just broken somebody's arm with a cane.
So, your point about mobbing could be valid, in that it might have been viable in their situation - but it might not have been; can't say based on what we were given.
And the fact remains, a person can hurt you badly with the first swing.
A factor we haven't really discussed, and one that is always true for cops and might be true for us - if the BG does score a disabling shot with the stick, he has immediate access to a firearm the moment later.