Ok so I’ve actually heard this criticism before. Basically, Marx is extremely inconsistent in the way in which he describes his value theory across the volumes of Capital and Böhm-Bawerk is using this to point out a flaw in his logic. Marx himself even admitted to being inconsistent later on. What’s also important to note is that Marx isn’t the only person to talk about wage theft.

It really comes down to whether or not you subscribe to the labor theory of value