The "sex without condom" that you refer to was found to be rape under UK law if proven. I'm not sure many people would consider rape to be a small crime.
The alleged offence... did not occur in the UK and therefore cannot be treated as a criminal offence by the judiciary.
Extradition is nearly always about things that didn't happen in the country that the person is being extradited from*. So are you contesting that extradition is inherently invalid in all circumstances? And, guilty of that or not, he skipped bail which is a 12 month imprisonment offence in the UK.
It is the same as speeding down the highway in Norway, getting a ticket, and then travelling to the Saudi Arabia without paying the fine or appearing in court in lieu of simply paying without protest. The Norwegian government can issue a bench warrant for the speeder and even with an extradition treaty with Saudi Arabia there is no way Saudis can claim speeding is a violation of the law if in fact there are no speed limits in that country. I am not saying there are no speed limits in Saudi Arabia, just using the country as an example.
No it isn't anything like speeding. A criminal act in Norway is alleged. That act would also have been criminal here. We have an extradition treaty with Norway, and they do not have excessive punishments for this crime over there, so we extradite. Simple.
*Gary McKinnon is a shameful counter-example, but at least we decided not to extradite him in the end