Greg, I don't think we are given enough information here to call this a fallacy.

However, I probably side with your overall skepticism about how formalism is used and abused.

The foundations of mathematical modeling are simple to state.

A good model is: a) a formal translation of informal language, of b) truth functional elements, that c) preserves validity of the home language inference.

Unfortunately, many thinkers leave out c) all together, are ignorant of b)'s limitations, and do not think about a).

Some conscious effort along the lines of a-c would improve our modeling in general.

If anyone wants to see a concrete but tinker toy example of a-c, consult any introductory text on formal logic and the rational reconstruction of material implication as a translation of the English "if, then." All the elements are shown clearly.