What part of having absolutely nothing to do with the company or its business do you not understand?
This is framing "violations of this code outside [spaces managed by the GCC project]" in a context more relatable to common men.
If an employee makes "transphobic comments in public outside of a work context" then upon what grounds does the employer have to terminate him for that? An employer should not be able to terminate an employee for something they do in their private time.
Likewise, GCC should not be able to ban someone for doing something not related to GCC. That GCC's code of conduct allows for that is preposterous.
My point was just that this is nothing new. It's always been the case that you could be fired for certain things that you did in your private time (e.g., historically, being gay). This is because what you do outside of work can affect the reputation of your employer. Within legal limits your employer has the right to freedom of association (just as you do).
Do "common men" not understand sensible examples or do you not have sensible examples?