This truly hit Gaven's soft spot. His own strength didn't match the Pillaging Destructive Arms; when merely using these arms for attacks during a confrontation, his strength indeed was thirty-three points (with the two-point bonus from his large body type).
However, when it came to a contest of physical strength, it was calculated based on Gaven's own body, including both inherent and external bonuses. His own strength did not even reach thirty points, putting him at no advantage against any single Giant Werewolf, let alone being simultaneously held by two.
The two Hunting Lords did not attempt to attack; they were just desperately holding Gaven down, leaving the assault to the ambusher.