Good you know the whole story.  You were obviously there?   The story states "another passenger was asleep Saturday in their ticketed seats. They insisted they complied with a flight attendant to return to their proper seats...   It also sounds like the air marshal asked them to leave after they returned to their seats?  Probably to make room for more pilots trying to make a flight somewhere else?

Sounds to me they didn't move fast enough or United was just having a bad day.