Infallible my ass.
Neither is diplomacy.
But please understand that it's papal idiocy and error which makes Infallibility so important, for it merely makes sure that erroneous papal opinions (and he's got a heapin' helpin' of them) will not become binding as part of universal doctrine.
It works only negatively. This is pretty satisfactorily explained by the following video from the Bad Catholics Bingo Hall (YouTube) which shows a curious connection between papal error and myocardial infarction.
(For your viewing pleasure. I will not mind of you laugh out loud.)