"That is a ridiculous excuse but that is how the court system works."
Actually Fox73, that's how the media works. The Advertiser reported the defence lawyer's submissions, not the findings of the Court.
Sentencing has been set for a later date. Defence lawyers do make submissions about the personal circumstances of defendants, some relevant some not. It doesn't mean the Court will take it into account when sentencing.
The example here might be relevant if perhaps a medical report from a psychiatrist confirmed that the denedant suffered depression as a result of the injuries and that contributed to the offending.
It's no excuse, but may be relevant in determining the severity of the sentence. There is quite a large scope of discretion available to the Court for most offences ranging from a suspended sentence to lengthy jail time, and all manner of things will be taken into account to determine where on the scale the particular offence should fall.