we can assume that he didn't land towards it on purpose
If he had chosen to make use of the radio all his problems would have been averted. A quick call would have told him the runway in use and alerted other traffic to his intentions. At the very least a call of "Full Sutton Radio, glider landing immediately RW04" would probably have prevented this accident.
I find it hard to believe that there wasn't time for that in a glider - he positioned for a right hand circuit to 04, after all. At glider speeds he must have had several minutes between deciding to land at FS and getting on the ground. Everyone here should be able to tune a radio eg to 121.5 and put out a call whilst flying a (practice) forced landing pattern with a high rate of descent.
Perhap for B Certificate and beyond (ie gliding outside the home circuit) glider pilots should be taught a few choice phrases for the radio and how to use the thing. I am sure his rebriefing from his CFI covered some of these points!