You need to read the cites. This just isn’t correct. The whole “bikes are stable due to the gyroscopic effect of the wheels” is one of those theories that is so cute it won’t die despite actual testing driving a stake through its heart 40 years ago.
Test bikes with additional wheels at appropriate angles designed to counter any gyroscopic effects absolutely do work. This has been known since the seventies.
Yes to racers having special rules, but it’s not specific to racing, it’s applicable to anyone who has decent bike handling skills and is willing to spend a little time experimenting with hard braking at speed, or moderate braking in a corner. The truth is that you can do quite a bit of braking in these situations, more than you would ever think you would be able to do. Maybe it’s not something you would do very often (or at all) as a casual rider, but it’s nice to know what can be done and at least experimenting a little bit with it.