I'm curious to when/if there are exceptions to this standard advice. When could it be a strategic move?
My stress levels decreased hugely when all communication was put into the hands of our lawyers - and it was eventually resolved with both sides walking away and paying their own expenses, which wasn't great as we had done nothing wrong but was probably the least worst option.
Honestly - if someone raises a legal action against you - talk to a lawyer who specializes in the relevant area and do what they tell you, which is likely to include no public statement without their approval.
Having been involved in a lawsuit last year, even after I won, I still don't dare to publicly talk about it for fear or repercussions. I simply ask myself: what do I have to gain, and what do I have to lose?
Usually the risks and impact of the things I have to lose outweigh the things I have to gain, and it's a good way of making myself shut up.
For civil matters, although IANAL I think similar reasons apply, so similar answer: Don't Talk to the Public. If you're truly famous enough to need to break this rule, then you need an attorney who specializes in high-profile cases like this.
Edit: By "cases like this", I mean an actor or athlete level of celebrity. Probably not John Carmack, despite how famous and awesome he may be within our circles. Really, the smartest thing is to just "shut up". Even though a false accusation is a genuine personal violation and you want to defend yourself, the best defense usually won't be DIY.