One of these things is not like the other.

I have no disagreement with there being something that delineates, for example, evolution and theories of selection, but I don't think it makes sense to draw the lines you do around "facts" and "subject matters" in contrast with "theories" of those things. There are facts at a fundamental level but these are just the observational data - the animals and their variation - not descriptions of the data. Beyond the data, it's all theory; the delineation is that we deal with theories at different levels. The difference between the creationist/evolutionist disputes and the selection disputes is not over some fact/theory boundary but rather over different theoretical levels, only one of which attracts unscientific theory construction because it is more basic than the other.

This is a somewhat pedantic modification of your claims but the important part comes with this:

As far as gravity goes, consider the fact that both Aristotelian natural place and general relativity are spoken of as theories of gravitation. They don't share any theoretical content: what they share is a subject matter. So the word gravity can also denote both the subject matter and a theory of that subject matter.

I don't have a problem with this necessarily, except to say that it is essential to realise that speaking of Aristotelian natural place as a theory of gravitation is retrospective in a way that Aristotle would not have recognised or understood, and that the use of the terms "gravity" and "evolution" as denoting both subject matter and theory is a relic of their cultural prominence. We use them as terms of fact not because they are facts but because they are enormously successful theories. The distinction is slight but important.

One of the issues that reveals itself in the analogy with UG, then, is that neither gravity nor evolution were constructed as self-evident truisms, which is what we are told UG is meant to be - the status of gravity and evolution as self-evident came only after the fact of successful theories being established and becoming respectable. Otherwise, why is it that no one spoke specifically of "gravitation" before Newton's universal laws? And why did no one speak of biological evolution before Darwin? Obviously, the subject matter was there since the dawns of time and life, but people were coming up with their own theories of explanation rather than inventing fact-equivalent terminology for the sake of it. I'm not saying that it's logically invalid to have given linguistic ability a (somewhat loaded) name before there was a truly successful theory of it but rather that is should hardly be surprising that people find it confusing.