Ignorance as defence for murder?

I’m not usually one for having a sense of moral outrage, but this story:

http://www.news.com.au/common/story_page/0,4057,11937683%5E1702,00.html

really riled me.

As far as I know, ignorance of the law is not considered a valid defence, so how far should ignorance of the toxicity of salt be considered one? Presumably if they had fed the kid bleach as a ‘punishment’ it would be considered murder. Or not?

Just wondered if you had any thoughts.

My first reaction is that this is just incredibly, deeply sad; the child was supposed to be starting a new life in a safe haven and this happened instead - did something go wrong in the vetting process or is this just one of those very unfortunate, unforseeable statistical blips?

I find it hard to believe they acted without intent to physically harm the child, but as with any case like this, of course, I haven’t had access to the evidence that the jury has seen.

Completely incidentally, I’m wondering how long it will be before some zealot with poor reading comprehension uses this story as an argument against homosexuality - the couple’s surname is Gay and the child was called Christian, leading to very easily-misunderstood constructions such as:

and

Totally different ball of wax. It sounds like in Australia, as in the USA, premeditated killing is definitely legally worse than killing someone by accident.

They meant to punish him in a stupid fashion, and went too far. They’re responsible for killing him, and I think five years is too lenient, but they got a lesser sentence because the death was accidental.

UK case - Australian Yahoo I think. Five years is too lenient, particularly when it really means 2.5 years or less in practice. There should be an added tarriff of a few years for the mind-numbing stupidity of it if it wasn’t murder.