Think of it like a terrorist organization occupying a town and them declaring themselves a new country. The original manufacturer has the trademark in their locale. They were also the primary manufacturer of all branded products, and according to the article, had many folks sign a letter where they would agree to only by arduino products from said manufacturer.

That is sort of like holding the town hostage with a bunch of guns.

From the sequence of events it does not seem like this was an "unplanned" event by Arduino SRL. It will be interesting to see what happens next after the Genuino brand starts getting pushed.