The offense is in attributing it to intrinsic differences between men and women. If you can supply some information that your sister's baby-monitoring experience was due to natural differences, vs., for example, conditioning by advertising, then that would be helpful.
I find your view on what is offensive fundamentally wrong.
Noting an arbitrary difference, like say "those ten guys are very interested in that woman's behind, while those ten women are clearly focussing on what this man is saying" is just observation (and not a reflection of my real world view, merely an example). Anyone who attributes negativity to either of these observations are betting offensive.
I should think aesthetics and personal feelings with regards to baby monitors can be helpful, in my example however, it wasn't. You chose to think it negative the female dominated forum judged differently than a male dominated one, if that's the case you are offending, not me.
