Yes that is true.Firing the pilot is a poor decision, IMO. I seems shortsighted of a company to turn its back and lose an experienced pilot due to a mistake. If there was a pattern of mistakes, that's a different story.
Amphibious operations are beyond doubt have the most risk for landing with the wrong gear selection....especially for high time float plane drivers.
I was fortunate to have started my sea plane career in an amphibian so it was easier for me to think amphibs.