My guess would be that either he felt it was such a monumental cockup that he had to off himself or his bosses thought it was such a monumental cockup that they had to off him.
It's called pooled hiring, and it makes sense when a company is hiring lots of people for lots of teams. Most large companies do this when hiring rates are high. You end up with better employee-team match when you interview a candidate first and then match them based on their skills/interest, rather than contacting them for a specific role they may or may not be interested in.
Has nothing to do with whether hiring is for headcount or other reasons
Also the idea that a country that has built the most extensive digital surveillance apparatus in the world will somehow avoid the temptation to use TikTok to monitor people abroad..