If someone has been publically slandering you and is now threatening legal action I think you're well within your rights to fight back however you see fit.
How far does "however you see fit" go? Escalation to the nuclear option is rarely, if ever the correct course of action.
It's the option Arrington usually goes for (i.e. Angelgate, Crunchpad collapse etc.)
I suspect in TechCrunch's case publicizing every lawsuit threat acts as a deterrent, resulting in much less legal hassle than they'd face otherwise.
Physical violence?
Kidnapping?
Arson?
From what I've seen of Mike Arrington, I have little reason to doubt that what Calcanis has said is true. That doesn't make his handling of the situation justified, but I think the hardon HN seems to have for Mike Arrington is entirely unwarranted, and motivated more by the hopes for favourable TC coverage than by rational analysis.
Sorry to say this but your baseless accusation of the HN community is also unwarranted.
Based on my experience, it's neither baseless nor unwarranted.