Military training area activated up to 27,000 feet

My first immediate response would be weather along the route, but the other jets are clearly flying a similar airway. So probably just a spacing thing, maybe have been onto dispatch and found out their gate will be occupied if they arrived following their planned route, so they take a turn to add a few minutes and free up the slot, so they wouldn’t have to wait to get to their gate. There is honestly a lot of possible reasons!

Helicopter parent much?