Whither Strict Liability?

I have just read this post regarding what is (if the facts are right) a rather alarming example of why "the innocent have nothing to fear" can be a dangerous lie.

Now, I don't know the details and truth of the specific case mentioned and that's not what I'm writing about here. Reading the post and linked articles got me thinking about the idea of "strict liability". Colloquially put, strict liability is the legal doctrine that, regardless of any fault, intent or wrongdoing you are guilty of a crime simply by an act its self (in the case above the possession of an unlicensed firearm, despite good reason). There are more through definitions of "strict liability" all over the internet, just search for that term.

I can see that there are reasons for wanting such a doctrine. If you are trying to prosecute truly dangerous individuals who have firearms then it greatly simplifies matters if all you have to do is prove that they did indeed have the firearm in question. However, surely there should always be a valid defence of good cause? One can think up any number of situations in which the morally right thing to do is to commit a 'crime'. When "strict liability" is applied to those actions isn't that inherently acknowledging that the law often has nothing to do with morality?

I'm very definitely not a lawyer and I'm quite aware that I may be missing something here. Please feel free to put me right or share your thoughts in the comments below.