The relationship between musk and Zuckerberg is general, even in a state of competition. It all started in 2016, when SpaceXs Falcon 9 rocket exploded, destroying a Facebook satellite. Zuckerberg expressed dissatisfaction, musk apologized and promised to launch the satellite free of charge.
From then on, there was a big difference between the two. Zuckerberg mocks musk for his fear of AI, which he believes may pose a threat to human survival. Musk encouraged people to quit Facebook, calling the social media platform terrible and even deleting the official facebook accounts of Tesla and SpaceX.
Source: Qiao JunJing, editor in charge of Netease science and Technology Report_ NBJ11279