From my understanding, Jack Ma having these troubles recently because he's filing the Ant Group IPO. Everybody was talking about the stock because everybody believes it would be skyrocketing. Also combined with the fact that the Ant Group is abusing rules under fintech's cover (eg: Banks need to follow regulations on the interest rate but the Ant Group along with other financial companies can get away with it, or they lure graduates to lend money they can't afford to pay back). These caused concern from the government because it has potentially huge impacts on society (most likely reap shit ton of money from people). As the government see it, if they caused such problems it's the government that has to deal with the consequence.

PS: Some information about Guo from the video. According to Vice, He was rich because he was close to high ranking officials, and fled because the Government ally he linked to was under investigation because of accepting bribes [0]. Everybody would know in China, a close relationship comes from bribing at least from those times, and bribing is a crime in most countries especially in the US. It seems to me, he callout corruption issues only because he's out of the game.

[0] https://youtu.be/LkOsgh5kcgQ?t=92