Goblins IX: For that, you shall DIE!

[Ravens_cry]

That's because it's the world in wich a game takes place, that doesn't mean that characters ACTUALLY roll a saving throw every time they touch Mr. Fingers. And aside from the noncanon statblock we have no evidence to suggest it's even possible to touch mr. fingers and get away unscathed.

Well, no, no more than you yourself make a Fortitude save every time you come in contact with a pathogen. However, Biscuit is someone who should be good at resisting these kinds of effects, whether you call that a Fortitude Save, Save verses Disease, or whatever.
If anything, the lack of in-world referral to the specific mechanic involved means he is more likely to succeed at resisting it, no unlucky rolling a 1 on something that he would be able to easily resist.