This isn’t entirely true. In some states, CA is one of them, the Good Samaritan law actually protects licensed healthcare professionals more. Bottom line is don’t be afraid to help.
I do agree that training is key and more important than training is practice. The skills are easily lost and when faced with a stressful situation that you are not used to being in, those skills vanish. Also, before you start taking classes you need to decide what you are most likely to encounter. Yes trauma is exciting and everyone wants to learn how to deal with it but the most common medical issues are going to be cuts and scrapes, upset tummies, sunburns, etc. Trauma care in the backcountry is easy: keep air moving in and out and keep blood in. How you do that is based on your training, experience, and equipment. With that said, with the proper training and experience you don’t need a lot of equipment and having a full kit but not knowing how to use it is a waste. Balance your kit with your training and experience. You don’t have to know everything, just delay death long enough to get the patient to a higher level of care.