The reports I saw showed those employees were shifting to crew another plane at their destination. Most likely some reason like sickness of staff forced the airline to fly staff to that airport as soon as possible.
Do you think they intentionally wanted to inconvenience passengers for no reason?
Of course not. For whatever reason they had to make room, and sometimes that means shifting some passengers to different flights. There is nothing malicious about it.
I have been forced off two flights in my 30+ years of flying, no I did not like it, and as a very large man I could easily have shown my azz if I wanted to, but why? What does it solve to have a temper tantrum?