Health protection is not one of the six topics. It is the reason there are six.
Every other reason this trade is regulated is downstream of one: the water people drink runs through pipe that somebody installed.
The whole argument in one sentence
A plumbing system is the only building system where a mistake can put something in a person's body.
Electrical can burn a building. Mechanical can make it miserable. A cross connection can put irrigation water, boiler chemicals or worse into a drinking water line, and nobody knows until people get sick.
Why the state legislates the subject
Texas does not leave health protection to whether a provider finds it interesting. It is a required subject in the CPE, alongside water conservation and energy conservation. That is a deliberate choice: the state is buying one hour a year of every licensed plumber thinking about the thing that licensure exists to prevent.
What it is worth to somebody who already knows it
More than you would think, and here is the honest reason. Cross connection control is not hard to understand. It is easy to get casual about after fifteen years without an incident. The hour is not there to teach you something new. It is there to make you look at your own habits once a year.
The plumbers who have actually seen a contamination event do not need to be sold on this hour. Everybody else should take their word for it.
Primary sources
Rules change and this page is dated. Confirm anything that affects your license against the board before you act on it.
Told straight, once
Status: the Texas Plumber CE provider and course applications are with the Texas State Board of Plumbing Examiners. Nothing is for sale until the board issues approval.
One email when a Texas plumbing rule actually moves. One when registration opens. Nothing else.