Eli & JJ - perhaps the compromise would be to say they were acting like 'scum', rather than that they are scum? - after all, we do not know them - they might be perfectly nice law-abiding citizens with a high moral standard most of the time, but just have had one thing too many go wrong that day (and yes, I agree it is unlikely but that does not make it impossible!)
as one commentator pointed out, what is the difference between a yoof seeing a flat-screen TV on the other side of a broken sheet of glass & helping himself to it; and a politician falsely claiming for one (which happened in at least one case)? Yet one will get 4 years and the other a slap on the wrist...
Sentences have indeed become disproportionate to each-other when (as Eli says) rapists get a shorter sentence. However a return to the Victorian concept of justice will help no-one (even if it could get past human rights legislation). the Community justice and Restorative Justice programmes do need revision and expansion, as they are more effective even now than prison for short-term sentences.
I think some sort of compulsory community service for everyone (with the option of it being in the forces possibly - but certainly only as an option) could well have some legs, if properly organised, but as with all such things, the devil is in the detail.