Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

You are partially correct. The general public also has protection written into in law in Canada (Yukon and Nunavut being current exceptions).

From the Ontario "Good Samaritan Act (2001)", Section 2:

Protection from liability

2. (1) Despite the rules of common law, a person described in subsection (2) who voluntarily and without reasonable expectation of compensation or reward provides the services described in that subsection is not liable for damages that result from the person's negligence in acting or failing to act while providing the services, unless it is established that the damages were caused by the gross negligence of the person. 2001, c. 2, s. 2 (1).[12]

What you are saying really only applies to people who are rendering aid in some kind of professional capacity, or for remuneration. (So a higher bar of competence should be met if it is part of your job to give such assistance, as the above text would not apply to you if it is your job.)

If you are simply helping someone with no expectation of payment, you are not liable for any damages due to your negligence, unless you are acting with gross negligence. And educating yourself in first aid would be a good first step in avoiding negligence.

Gross negligence requires recklessness, or purposeful ignoring of health and safety. If you are acting with good intentions and with due consideration for the health and well being to the best of your ability, it is difficult to see how the bar for gross negligence would be met.

Such "good samaritan" laws are a common feature in many countries around the world, although it should be noted that there are regions (including some in Canada: Yukon and Nunavut) where such laws do not exist.