This is grossly and absolutely inaccurate and false.
Captain Edilberto Valdez, a former airline pilot at United Airlines, Champion Air and Skywest Airlines who has held various positions in the aviation industry (including line check airmen, Boeing 727 training director), got a B.Sc degree from Embry Riddle Aeronautical University and taught corporate, military and NASA test pilots, uses Microsoft Flight Simulator X (which, according to your own incorrect logic is a “game”, since no part of it is FAA approved and no such approval/license for FSX exists) at his flight simulator classes to teach his private pilot students at Cypress College in Southern California, where he is also the assistant professor of Aviation.
Rod Machado, another very popular flight instructor, author and aviation speaker, himself visited Captain Ed back in 2014 at Cypress College to speak with his students, learn about their success rate (which is quite good) and witness how these simulators driven solely by Microsoft Flight Simulator X actually work.
An article about Rod’s experience and meeting with Captain Ed was published by AOPA (Aircraft Owners and Pilots’ Association) even, in case you think I’m making this up:
Captain Ed in his classes also uses ATDs and BATDs assembled by Elite Simulations (Elite have been doing this since 1987) and certified by FAA, CAA and EASA. The following is how developers at Elite Simulations address Microsoft Flight Simulator 2020 (spoiler: They don’t call it a “game”):
Image source: Plugins / Drivers & Software updates | ELITE Simulations Solutions AG (flyelite.ch)
Image source: New ELITE product line ALTURA | ELITE Simulations Solutions AG (flyelite.ch)
Last but not the least, Prepar3D, another Microsoft (ESP) product and a copy-paste fork of your “game” Microsoft Flight Simulator X, has been in use worldwide for more than 10 years by various air forces for solely professional flight training purposes.
Also worthy of mention that the legacy, FSX ESP-based flight model is already included in MSFS 2020 (if a developer wants to use it for whatever reason), and another professional flight simulator development group Pro-sim (whose products are used in professional airliner training) have already released their A320 for your “game” MSFS 2020:
You can learn more about Prosim and their customers here: Homepage - ProSim Aviation Research (prosim-ar.com)
Nevertheless, I sincerely hope calling Microsoft Flight Simulator 2020 a “game” makes you happy and helps you sleep better at night