This is not Jiang Chen being alarmist, it is indeed true.
If the Ten Great Sacred Grounds of the Eternal Divine Kingdom of the Myriad Abyss Island lose control over the island, allowing the descendants of deserters from the ancient battle against the demon sealing to seize power, then the island will completely lose its vigor, leaving only a group of selfish cultivators.
In that atmosphere, who would go outside the region to eliminate formidable foes? Who would protect their homeland outside the domain? This is definitely not something those deserter descendants can accomplish.
Of course, Jiang Chen did not clarify these matters now.
After all, Yan Qingsang and Huang'er were considered descendants of deserters from that ancient battle against demon sealing. Although their lineage had some vitality, their status wasn't enough to influence the big picture.