Why not? Would you have rather fought the Germans here?
That statement is not very accurate historically, and quite naive. The war in Europe was at a complete standstill, they were dying over yards of land, they couldn't have projected force over the ocean if they wanted to. Besides, it was a fight like so many others, over the reach of Empire. The British, French and Germans had been going at each other for centuries, the only difference in that war was we intervened. Causing a imbalance in powers that may have led directly to the rise of Hitler and his ilk.
The Germans weren't interested in taking us on.