That’s true, but close to my point. Rav Feinstein obviously does not condone the fact that people in shidduchim refuse to mingle for the sake of shidduchim. It sounds like he holds it is proper hishtadlus to go out of your way and mingle with a member of the opposite gender for the sake of finding your zivug. I wouldn’t pasken from a story you heard third hand over the internet, but people should definitely ask their LORs.
I also personally heard from a close talmid of Rav H. Leibowitz ZTZ”L that one time a certain Rav said girls should be “understanding” when dating yeshivah guys because they have no experience talking to girls due to spending the large chunk of their lives in front of a gemara in yeshiva. R’ Leibowitz was adamently against this statement and said a guy who claims this excuse about himself is lacking in his mussar and middos. If you learned mussar properly in yeshiva you should have no trouble talking to a girl like a mentch.