Can't quite make out what went on?
Why would you run a train missing stops direct to Sutton?
If you're coming out from London Bridge via Tulse Hill, there are three ways the train can take to Sutton
via Wimbledon
via West Croydon
via Mitcham Junction
As far as I can make out, there was some sort of issue on the booked route / southbound track, so the train was being sent to Sutton via another of the routes and then back along the Northbound track to make all of the stops but in the reverse order. But that message didn't reach the comprehension of all of the passengers for whatever reason.