You realize wage theft is documented as greater than all other forms of theft combined in the US right? It isn't some fringe theory, it is established fact.
If so, then we can safely call that behavior uncapitalistic. That's how the definition works. FWIW, I knew very little about wage theft, until researching it at your prompting, which I appreciate. Seems like wage theft is rarely actual theft, and most often a violation of contract, but in either case it's a violation of capitalism's seed principles. Sometimes wage theft is neither theft nor contract violation. That's my impression from Wikipedia, at least.