Very unfair and skewed way to look at it... A single article from years ago! It's not like you hear about boats blowing up every week due to gas explosions!
I, for one, think that from a purely environmental point of view, a propane fueled outboard is a fantastic development! At sea in commercial cargo vessel the huge two stroke main propulsion engines are changing to "dual fuel" and even propane powered versions. This is a huge development for environmental considerations.
I do think though that when a new technology is introduced it should be that the developer/seller provides training to the consumer. In other words to own that Tohatsu then the dealer/seller should provide training to use it... funded by Tohatsu!