He didn't let Xun Tu release these Yang slaves immediately, because just as Xun Tu said, it is extremely difficult to reach the human realm, with a Ghost King personally guarding it. Although the Ghost King usually remains behind the scenes and is unlikely to act unless forced, the path is still not easy. If these forty Yang slaves left on their own, they would likely be captured by other forces as soon as they stepped out of Xun Tu's territory, or even devoured directly by ghost beasts.
Despite Xiao Qiang's desire to save them, he is no saint. His own situation is quite precarious, and with one misstep, he could fall into an abyss—let alone taking along these forty Yang slaves. Therefore, letting Xun Tu settle these forty Yang slaves is the most helpless yet the best plan for now.
"Don't worry, sir, I will definitely settle these forty Yang slaves properly," said the young girl from the "Son of Reincarnation", stepping beside Xiao Qiang and tugging at his trouser leg.