This really is dead simple.
If you were'nt there, you don't know exactly what the particular passengers attitude was. None of you can comment. None of you can state that the decision was incorrect. Unruly passengers are a menace. They can be a risk to flight safety. They can certainly cause stress amongst crew and passengers. They must be seen to be treated with zero tolerance. The message may then get across......behave properly !
The Captain was in charge, he made a judgement, we should support that decision 100%, end of story.