Long back, I used to work for a freight forwarding company who were just starting up with their own platform for freight forwarders. They have built a unique platform to integrate freight forwarding as well as trucking industry in a single go. I had a similar kind of agreement executed with the while joining the company which stated I can't join a freight forwarding business for another 3 years after leaving their company. The Judge has taken right decision to safeguard the intellectual integrity of a business!
However what bugs me is why these ex-employees continue to create their own mining pool if they have an existing non-compete clause with Bitmain. Bitmain might did a dirty trick by hiding the clause itself under their contract rather than outright telling that a non-compete clause such exist. Non-competes and NDAs(Non-disclosure Agreements) clauses are supposed to be said vocally and is clearly seen in their contracts so that they are fully aware of their contract. These three executives might not even have a clue that's why they got trapped by Bitmain. I have a feeling that this is a possibility here since they did this kind of dirty tactic to Micree when he got ousted.