I would have said that a technical offence was anything that wasn't foul play?
I had the same thought, and I imagine that's what they meant.
However they goofed as collapsing a maul speciically is foul play
[LAWS]
10.4 Dangerous play and misconduct
10.4(k) Dangerous play in a scrum, ruck or maul. The front row of a scrum must not rush against its opponents.
Sanction: Penalty kick
Front row players must not intentionally lift opponents off their feet or force them upwards out of the scrum.
Sanction: Penalty kick
Players must not charge into a ruck or maul without binding onto a player in the ruck or maul.
Sanction: Penalty kick
Players must not intentionally collapse a scrum, ruck or maul.
Sanction: Penalty kick[/LAWS]
and
[LAWS]17.2(e)
A player must not intentionally collapse a maul. This is dangerous play.
Sanction: Penalty kick[/LAWS]