My theory is that the
inhabitants of the Gamma Quadrant may have a totally different psychology than the Alpha Quadrant.
They're used to using threats and violence to make a culture to obey them without question.
With all the genetic engineering, threats, fear conditioning, and bribes, that may be the only way the Dominion knows how to deal with solids.
Weyon actually broadcast a speech to all Cardassians telling them that Jem Hadar just destroyed one of their major cities, for the acts of a few, then smiles and asks them to resume fighting the real enemy, the Federation, etc.
I noticed an episode where the Founders decided to breed a new strand of Jem Hadar specifically designed for combat in the AQ.
The fighting skills I could understand, but they also said they were 'psychologically' designed to fight in the AQ too.
It's like a small clue that the psychology in both quadrants may be different.