It's a rhetorical argumentation technique. They make it seem like it's inevitable and follows naturally from the obvious fact that you are an employee 100% of the time, so they don't even need to spell out the specific point in the contract, implying that it's not just a technicality in the contract but something fundamental. Which is of course not true, as in many countries you can't have such valid terms.

I think you might be giving much credit to random internet commenters. They probably just like to say "technically speaking".

I'm not talking about random commenters. I mean the manager who wrote "... you are an IBM employee 100% of the time ..." .