mdd- to get back to halachic discussions is refreshing- You have a point of “se-jog” as far as knee or above. However, because the borderline is so unclear, it is not right to attack women who do not strictly confirm to your expectations.
Your point about wearing opaque tights without a skirt is valid. Yet, I wonder whether it circumvents the issur of “tefach be’isha ervah”.Don’t get me wrong- it would be very provocative but does it fit the requirement of covering the “tefach”?