I don't know why the use of camphor medicinally has been restricted in the US. I use a camphor ointment that I actually purchase online from outside the US. There are camphor ointments still on sale in stores in the US, but I prefer the original.
Camphor salve is a fantastic remedy for aches and pains, especially those caused by arthritis. It is my go to salve during the winter months when cold weather makes my knee arthritis act up. My mother also uses it regularly to treat neck pain caused by a neck injury. Camphor is a gem of a remedy and in my experience it's safe.