On the other hand it doesn't explain why they didn't look at another orbit that they did have enough fuel for. Was this a decision that had to be made immediately?
A group of communications satellites have to be deployed in a synchronized way, to continuously cover the area they target. Changing the orbit of this satellite would mean changing the orbits of the other 16 satellites as well. Also I'm pretty sure you have to license a particular orbit ahead of time instead of just picking whatever is convenient at the moment.
Issac Newton got quite bored after becoming immortal and now has a little booth set up at the patent office. Don't take the piss out of his wig, otherwise you will get nowhere with him.
I strongly suspect it was so that they could collect the maximum amount from insurance as quickly as possible. No other explanation makes as much sense.
They didn't fire at all because there was a risk that they might have hit the ISS. SpaceX was operating under NASA's rules and NASA had a safety window where the Falcon 9 could/couldn't fire its second stage.
The risk was almost certainly overstated, but NASA is understandably paranoid about things hitting the ISS.
