Unfortunately that happens, especially when the nature of the crime is abhorrent. People get wrongly convicted of murder all the time because the crime was so heinous that they felt the psychological need to convict, to punish the person who did it, blurring in their minds the fact that the person on trial before them may not have been the actual perpetrator.
I agree with 2Vermont, that most jurors look at the facts pretty impartially. Your above explanation is not my experience and i've been on 2 murder trials. My experience is the exact opposite - fear of sending a person to jail. In both murder cases, we could not reach a verdict because 1 person couldn't bring themselves to condemn the defendant. They didn't question the evidence, they just said they couldn't vote guilty. A shame.
(The good news is, in case 1, the defendent accepted a guilty charge for a plea deal...so they were actually guilty (as most of us knew). In case 2, our lack of unanimous ruling meant a re-trial. After the case, the prosecution shared with us a bunch of evidence that had previously not been allowed, but would be allowed in the re-trial. I'm convinced the re-trial would convict but I never checked the status of the 2nd case.)
However I would add that a murder case usually involves more hard evidence than abuse cases, which are more circuмstantial. So, on the one hand, it's easier to sway a jury in an abuse case (if you're a good lawyer) because the evidence is based around a "story" vs a murder trial, where you at least have SOME evidence on the body and the "story" is not "he said, she said", which is usually the situation for abuse trials.
Secondly, in Austrailia, what is the level of guilt required? "Reasonable doubt" or just "more than likely"? This would make a big difference.