Very interesting piece of history, there.That's not what I heard. Knife is held in the right hand, because cutting is something most people do with their dominant hand. Fork is used to hold the food in place while cutting, which is a supportive task, to be done with the non-dominant hand. In the US, many people cut with fork in left and knife in right, then switch the fork to right to bring the food to their mouth. It is said that an American spy in Germany during WWII was found out because he was using his knife and fork the "American" way.
I think that us lefties do a fair number of things the right handed way, because we are raised in a right handed world.