Representation is a normative relationship. Causation is not. What I mean by this is that representation has correctness conditions. You can meaningfully say "That's a good representation" or "That's a bad representation". There is no analog with causation. There's no sense in which some particular putatively causal relation ends up being a "bad" causal relation.

This is an important point, and if I agreed, I think I would join you in rejecting the correspondence theory of truth. (In my case, I'd just go to quietism - a polite refusal to have a "theory of truth" beyond Tarski's formula - rather than pragmatism.)

But here's the thing. There can be a bad causal relation, with semantic significance. If "horse" utterances are sometimes caused by cows, but usually by horses, and the cow-to-"horse" causation relation is asymmetrically dependent on the horse-to-"horse" causation relation, then the cow-to-"horse" causal route is a bad one. The asymmetric dependence is a sign that "horse" means horse, and not cow. (H/t Jerry Fodor.)