Having the semen not containing the DNA of the accused is a technicality?
The guy was prosecuted for rape. The DNA didn't match. That's beyond reasonable doubt, that approaches No Friggin' Way.
I'm not saying this particular man's release was based on a technicality.
But, yes, DNA could be a technicality. Please reread my first post where I gave an example of it as a technicality in a local case.
It is possible for two DNA samples taken from the same individual not to match.
This happens in cases of people scientists term chimeras.
Science ASSUMES such cases are rare
And besides, it's convenient to ASSUME such cases are rares, else it might spoil their fun releasing prisoners.