This was the Law of the Universe. Since there weren't any Laws here, no one would be able to activate their sacred arts unless they were experts with their own Laws. Moreover, Laws weren't the only things that weren't present; there also wasn't any elemental energy. That meant that regardless of the elemental attribute of one's spiritual roots, he wouldn't be able to use any sacred arts.
Mo Wuji cultivated the Mortal Technique and his Mortal World had already taken shape when he was only in the Heavenly Immortal Stage. At this moment, his Mortal World's Laws were complete and they were continuously being refined.
On the other hand, this stone statue was actually able to attack despite not cultivating the Mortal Technique. From the looks of it, this stone statue wasn't simple and had his own techniques.
