Sigh. Making a definition of facts is one thing, determining what specific assertions get considered a fact - that is,one’s epistemology - is another thing. Agnostics, just like everyone else, are sure about their epistemology.
The criteria for what constitutes a fact, what kinds of evidence, testimony and which experts determine facts, that’s where it gets complicated, not the definition per se - since definitions - in the dictionary say - set those issues aside, since they present abstracts without getting into epistemology. Even amongst secular educated people you find extreme disagreements about ‘what the facts are’. So when I read someone - in this case you - say something about ‘the facts’ as if ‘we all know what those are’, I think they may not understand, and perhaps one should in a philosophical context, that the word ‘fact’ in contrast to something else, does not really give us any information. It sounds simple, but epistmologically it is not. A suggestion: focus, on day, away from the secular/religious divide, and watch two secular groups, with differing stances on something: politics, how to raise children, male/female issues - see how each group throws ‘facts’ at the other. They may all even agree on the definition of ‘fact’ but have differing epistemologies and different experts they trust and so what they consider factual differs.
So when you say ’
You are confirming what I said. They have certainties about epistemology, and they see certain things as facts and they have utter confidence in their own epistemological beliefs - iow how one arrives at the categorization of something as a fact. Not that all agnostics agree with each other, but each is an idolator - by your extreme definition of idolatry - of their ideas about epistemology.
One can look at one issue - does the agnostic believe in God or not - and say, they are not idolators. Or one can look at how they justify their agnosticism, and find that if we use your extreme and idiosyncratic definition of idolatry, agnostics also are completely sure of certain things. And yes, they call those things ‘facts’ or they are ideas about epistemology.
One can, yes, walk away, shaking one’s head retaining confidence in what one considers obvious. That is always an option. But that would have to be based on a kind of idolatry, as you define idolatry. Just look at all the things you are sure of about religious people. And yes, you consider them ‘facts’. Many of them I do also.