Huck,
The landing would be the same where ever it took place - so it may as well be nearer to destination. If there are no indications of damage to the aeroplane then another 6 hours won't make a lot of difference.
As long as the fuel is recalculated to allow for it (something the Hapag LLoyd chaps didn't do) then there is little or no reason not to go on. They would also, I presume, have had to dump fuel for an immediate landing - much better to burn it usefully to cross the Atlantic than throw it into the sea.