Jos also was very against Horner, so Max by default also supported his dad. It was Helmut, Jos, Max, Austria vs Thai and Horner. Thais were under constant pressure to justify Horner, but as performance dipped + combined with the scandal, the Thais withdrew their support.
Going by Helmut words, it also seems like he was backstabbed by the Austrian's, hence his comment about 'you think you understand people'. There are no saints in this fight, everyone fought dirty, including the Austrians with their constant negative PR against Horner by using their Dutch journos. Horner thinking he could somehow get the better of a 49% shareholder, with operational rights to F1.
Verstappen might be calm now, but the core team around him has disappeared fast, he doesn't have people as many people he feels loyal too, if the cars in the next 1-2 years don't perform, it will be easier than ever for him to jump ship. If Verstappen jumps ship, there's a big slump coming for Red Bull.

