Yes, there was little doubt FDR was favoring England...
But before Dec. 7th Hitler gave his Uboat captains STRICT orders to do all they could to stay away from American ships.. There were accidents and mistakes so there were incidents between US ships and German uboats.. But it was clear Hitler was doing all he could to keep the US out of the war..
So IMO his decision to declare war on the US(and BTW the US was the ONLY country Hitler declared war on) was puzzling..