Are you saying receivers now come without threaded FM jacks?
If so, this is not good news.
I believe that "push-on" connector is a cheap substitute for a threaded "F" connector. It will fit over a standard, threaded, "F" jack. Methinks it's made for those who are not mechanically inclined enough to screw on a "F" connector.
These have been used for low-line video interconnects for years, particularly at Radio Shack back in the 80's and 90's.
Given my druthers, I'd go for the threaded ones any day. They make a more secure connection.