FAQ tells you can claim a draw by threefold rep. But does not tell you how to do it.
There is a chance that the other lad too did know the threefold rep rule.
Between them they have played 314 games with only 7 draws.
The OP was involved in a 3 fold rep before, Game 7482613 moves 63-71
but it may not have been him who claimed it or perhaps it was just agreed.
(His opponent in that game 'kqnbrp' has played 149 games with only
3 draws so there is a chance he too was not aware of the 3 fold rep rule.)