I reckon this is very regional. We have areas that have both requirements. One place (only one I know of) has angle parking where you are required to back in. Some people are comically bad at it. We have other lots that specify "Nose in parking only" - these tend to be tighter lots. But these are private rules set by the lot, not by law. Conversely, our local Costco has spaces so big you can pretty much open the door 100% and not hit the car next to you. You could probably park an Abrams tank within the lines at Costco.
I don't think it's controversial to say that the average driver can more easily pull in forwards to perpendicular spots. Reversing into a defined/confined space is not so easy for some. I'm not aware of any locality near me that forbids reversing out of a parking space. Most lots are on private property, and most street parking is parallel.