I think it would be OK if the tomogaras didn't want to interact with humans. This was explained before - I don't quite remmember who (Deathscyther probably)... For normal people Tomogaras are monsters, aliens. They would attach what they don't know...
Can you imagine how owr government would react if they found beings from Guze?
So Yuji wants to make them co-exist, live together and share the new world - that's one of the reasons Justus is so important... and also all the Flame Hazes. I mean, they just changed their reason to fight.
EDIT: I've also seen the second translation: good like always and much more in tune with the novels. Yuji is a strong being, non-human. So, he can live forever by Shana's side!!