Isn't Stone Mountain technically a private park? They're probably not 'real' cops and they probably don't give a crap.

Now, I do think the two abreast thing is a little silly to get in a huff about as if they're going with traffic, you can have way more than two abreast in a single lane (and the cyclists should be worthy of a full lane if they're going at the speed limit), which would make the group more compact and easier to pass in the left lane.