ir, you and I believe that what our Gedolim poskened regarding tznius is halacha, but some in the CR don’t see them as their Gedolim. They say their Rabbis poskened differently and everything else is chumros.(No not gavra, whom I answered looks at these halachos as chumras.)
If you look at it that way, then these chumros are essential to our continued adherence to the halachas of tznius.