What's being talked about is the broader social expectation that women perform reproductive labor. I don't think Bay_of_Piggies is claiming that to be fact or their own opinion. I mean, that this expectation was nearly universally held, and still is held by many, is not to say that it is right or good. Women were considered property in no small part because the majority of them were capable of and expected to make babies. That expectation is misogynistic and is a mainstay of the patriarchy. And yes, it would additionally be a TERFy thing to say if one were to claim that only women were capable of having babies, but it's not at all TERFy to recognize that this definitely was (and unforrunately still is to a degree) a widely held belief.

I may also have something wrong here, including the possibility that I may have misunderstood what you were even asking or unclear on. If so, I don't mean to unhelpfully explain the obvious.