He didn't waste his time doing anything. That's the thing: He did nothing! The US abstained.
I think there are some more spiteful reasons in this decision, whether it be due to Trump's clear pro-Israel stances or Obama's dissatisfaction with internal Israeli policies. Regardless, I think it's foolish and against the US policy to leave the fate of the settlements up to the Israelis and Palestinians and not get involved. Yes, we've condemned them officially, but it was held to be best to not get involved beyond that since it could have effects on the peace process. And yes, it will make things a bit more complicated.
I don't think Obama outright hates Israel, but he doesn't understand much. He put too much emphasis on the settlements and mollycoddled the Palestinian leadership, which is not the best for peace. The settlements cannot be THE thing causing disagreements - not when strong disagreements exist without them - but his administration did go about as if they were and didn't hold Palestinian resistance to peace to any responsibility.