This case highlights one of the differences between UK law and Austrian law. In the UK sex with a child under 13 is always classed as rape whereas consensual sex with a child under 16 is classed as the lesser offence of sexual activity with a child.
In Austria the age of consent is 14, two years younger than in the UK. A number of websites state that sex with a child under that age is statutory rape in Austria. This is wrong. Consensual sex with a child under that age is classed as a form of serious sexual assault (although there is an exemption when the perpetrator is less than 3 years older than the child). The sentence for this form of sexual assault is up to 10 years in prison, rising to 15 years if the child is seriously injured or becomes pregnant, rising even further if the child dies as a result of the assault. Consensual sex with a 10 year old is not classed as rape in Austria.
In this case the attacker was convicted of both sexual assault and rape. The sexual assault conviction stands but the rape conviction has been overturned as Austrian law requires evidence that the attacker knew the victim did not consent - this is similar to UK rape law for victims over 13 where the prosecution have to prove that the victim did not consent and the rapist did not reasonably believe that the victim consented. The Supreme Court in Austria was of the view that the first court failed to establish whether or not the attacker knew the victim did not consent and therefore the conviction could not stand.
The Supreme Court in the UK would never make such a decision as it would be clearly contrary to UK law. However, the decision appears to be in line with Austrian law.
I don't think anyone is arguing that the child in this case consented. The question is whether it has been proven that the attacker knew the child did not consent.
This is certainly not a case of the Supreme Court going out on a limb and coming up with a strange decision. I don't know how much attention this case is getting in Austria or whether it will lead to pressure to change the law. I hope the law does change in Austria. In my view sex with a child of this age should be treated as rape regardless of consent.