Avi, that apocryphal story, even if it is half true, is said to take place in the CC’s home at his Shabbos table. NOT at a public gathering with masses of both genders in attendance, with music playing and the women dressed to be noticed.
Catch, that was only at the Tendler wedding, who was much more modern than the Feinstein family, and it was his decision to mix his friends and others. Not Rav Moshe, whose sons’ weddings had separate seating. Dr. Tendler met his wife at the New York Public Library, the shidduch wasn’t made through Rav Moshe.