The Beastmen reject the Magic system, not because it isn't powerful. On the contrary, all Beastmen know the might of the Mages.
The reason they reject it is partly because it differs from their combat ideology. Beastmen prefer brutal, blood-soaked battles, which better kindle their fervor.
Furthermore, because they are not skilled in it, naturally, they tend to disparage it.
This boosts the morale of their tribe, preventing them from collapsing when they encounter the Magic system.
However, contemplating the massive appearance of Magic Users by their opponents leaves them feeling somewhat weighed down.
Only Zhao Guang is manageable. Although they are highly vigilant, Zhao Guang's personal strength is extreme, while his subordinates are less impressive. Moreover, their relations with Zhao Guang have been generally good, without open conflicts.
Those small maneuvers in private are commonplace for people at their level.