I can't accept that. Hans certainly knew Nicholls was close but, in my opinion, didn't know exactly where he was when he 'turned right' towards the fence. It all happened so quickly and, worst case, Scott could have been seriously injured or worse. No doubt Hans thought Scott could take avoiding action which fortunately he did but there are occasions when none are possible (viz. Nicki Pedersen on Greg Hancock in the GP).
As for Scott returning the favour, well it was hard but done over a longer period of time with Hans having plenty of opportunity to know what was coming and act accordingly.
The sportsmanship issue is a little harder to call - no doubt Scott felt that what Hans had just pulled could have seriously injured him as well as the fact that the adrenalin must have still been pumping after a race like that.
It was exciting to watch though!