~snip~
Another explanation may be that multiple people use the same account, or multiple accounts, which is why you can notice differences in his posts, in terms of writing style, grammar and AI usage. It's extremely evident in posts that he's expressing his opinion and in others that actually require some knowledge to answer, in terms of definitions, technical specifications etc.
I would be inclined to exactly that theory, considering that the manager wholeheartedly defends exactly such shitposters who could actually be part of the alt network that the company bought to promote itself on the forum. I wouldn't be surprised if they then hired one or more people to manage that network, and of course they use AI and paraphrasing to do their job.
It is obvious that such a way of promoting pays off, because the investment in buying alt accounts is returned in the way that they do not actually pay unique members to advertise them. Unfortunately, apart from the persistent report such post and the hope that some of the global mods will react with a ban, red tags or flags are quite ineffective for such things.