I think #2 absolutely deserves someone to be a dick back.
And I think it's just making it into a bar-fight. There are people who can do it well, but they know what they're doing and are the exception that proves the rule. Otherwise, you risk escalation and you cannot take the moral high-ground; you've lowered yourselves to their level with the excuse of "they started it". (Which was never an excuse when I was growing up. Maybe things have changed.)
The #2 anti-trolling technique (after ignoring them) is to respond to them with honesty and logic. While I think we over-use the term "troll", it does bear looking into. A true troll will respond with more, while people who aren't really trolling (knee-jerk reactions, e.g.) will start to act in kind.
So yes, if we can stop escalation, all's the better. If not? Sure, let's bring out the big guns.
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important edit:
I agree with "it's degrees", but I don't think the first response to defending oneself should be to make a sick burn. It should be "does this need defending?"
The second should be: "How is the best way to defend this?"
I cannot think of any situation where "with being a dick" is a good answer. A fun answer, sure, but not if your goal is solving the problem.
