There are really only two rules for commenting on this site – keep it civil and keep it on-topic.
Don’t use words or phrases that are meant to offend. Don’t insult others. Don’t call names. No slander, libel or defamation. Criticize their viewpoints till you’re blue in the face, but don’t get personal. Don’t use ad hominem arguments; it’s the other person’s opinion you’re addressing, not the person him/herself. And don’t use curse words. If you can’t express yourself without them, you need to think more clearly.
Keep to the topic of the post on which you’re commenting. If you want to discuss something else, do so elsewhere.
Keep to those rules and you’ll be OK. Violate them and I’ll delete your comment.