Those from the Ten Thousand Demons Ridge could see the tremendous threat Lu Ye posed to their side, and they wished to eliminate that threat to prevent future troubles; the Haotian Alliance could likewise not fail to see this.
To Ten Thousand Demons Ridge, Lu Ye the Sect Destroyer was a disaster star, the source of chaos and calamity, but to the Haotian Alliance, Lu Ye was the young generation's rapidly rising star, a pillar to stand against Ten Thousand Demons Ridge in the future.
When one's stance differs, so naturally does one's attitude towards people and things.
If Ten Thousand Demons Ridge wanted to kill, then the Haotian Alliance would want to protect. Since ancient times, the confrontation between these two camps has always been thus; neither side would easily fulfill the other's wishes.