"Why are so many people turning to homeopathy/naturopathy?"
It's a $600 bill and a month on the wait-list to get a fifteen minute doctor's appointment, in which the doctor will tell me to lose weight and accuse me of faking my symptoms for drugs.
Meanwhile, homeopathy stores are walk-in, and the employees will spend as much time as you want validating your problems, then send you home with a "remedy".
People aren't falling for quacks because they're stupid, they're falling because they're desperate and the medical system is actively hurting them.
The answer to "is that legal" is, in the US, often "no, but the process of reporting it and holding them accountable is so difficult and painful that it may as well be legal for anyone the government doesn't already have it out for".