Placing yourself in the correct place in the queue is not queue-jumping and is most certainly not inappropriate. Not all queues are first-come first-served.
It didn’t sound like OP was checking boarding passes while angering the two dozen people he cut ahead of.
It appears I’m in the minority here, but I’m sorry, it’s the airline’s job to enforce their boarding policies and passengers’ jobs to stand in the right place. One doing a poor job doesn’t excuse the other behaving inappropriately.