Oh, I don't mean swearing and eloquence are mutually exclusive.

But eloquence isn't binary; it lives on a gradient. Where there's a common, monosyllabic, four-letter word, it could be displacing another with a fair likelihood of being more interesting.

In fact, I'd argue your Shakespearean actors are far more likely to be making a compromise than an ineloquent person who'd otherwise drop the modifier or use a simplistic alternative.

So they're not rendered ineloquent as people, of course; but less eloquent than they'd be without that crutch.