Besides the point/argument laid out in the article, could you mention any possible reasons you think this may have happened? Would help to hear.
From the wording of the email, it sounds like his previous ventures might have been doing something shady and those accounts are linked to the startup account.
That's distressingly vague, especially when he provides screenshots of the recent termination emails. If there wasn't more to this, you'd expect the history of that other account, which is pretty clearly relevant here, to be laid out in a lot more detail.
I agree that Google is prone to arbitrary and Kafkaesque behavior, but this instance smells fishy.