Yes, it was justified. If I had been online and seen that flag raised, I would have done the same thing. How the comments got brought to a moderator's attention is irrelevant. Once a moderator is involved the entire situation gets reviewed and the steps needed to stop the disruption to the community are taken.
Your behavior in chat earlier that evening also ended up being brought to the attention of the moderation team, and J.R. did try to give you some guidance. If you want to avoid similar situations in the future:
- Don't call people names, belittle them or disparage them personally.
- Don't ping people over and over trying to continue a discussion when they have indicated they don't want to continue that discussion.
- Remember that the community here are all volunteers. No-one is obligated to answer your questions, explain things to you until you understand them or engage with you until they understand your position.
When you reach a point in the discussion where you start to repeat yourself, stop posting. The discussion is no longer constructive, so just let it go and spend your time and energy on something more productive.