Mo Wuji was different from the other cultivators because he cultivated with meridians and didn't have any primordial spirit or spirit roots. As long as all 108 meridians formed spiritual circulations, he would be able to cultivate.
Others might need to find a quiet place to cultivate but Mo Wuji was able to cultivate while retreating. Mo Wuji was not the only one who could do this as Da Huang could the same or even better than Mo Wuji.
Da Huang had 108 meridians and also 108 spirit channels. However, Da Huang learnt from Mo Wuji so he didn't cultivate his primordial spirit too. Moreover, Da Huang had a purer heart and mind so he was able to cultivate well even while retreating.
Everyone was dazed by this change because nobody expected such a huge transformation in the God World.
