The hadith simply shows that Umar (RA) had a deep understanding of Islam such that he could recognize what was good even before Allah gave a clear command regarding it.
It does not mean that Umar (RA) is the reason something happened but rather that Umar (RA) understood what was in line with Islam. Allah confirmed what Umar (RA) said because it was in line ...
It is Absolutely Haram.
Brother, One of the distinguishing features of Islam is the rulings on Modesty. Islam teaches us modesty and is strongly against shamelessness.
Prophet Muhammmad (SAW) says:
'The Iman has 70 departments and haya (modesty) is one of them'
In Quran Allah says:
'Tell the believers to lower their gaze (from looking at forbidden things), ...