As an infrequent player who can only get a few games in a month, rarely checks the forums or discord, I think I'm with the majority of players (by count if not by playtime).
My opinion: I do not care about this rule one way or another.
However most of you should be banned for rudeness. Fucking hell. It's just changing your name.
Edit:
To add few other thoughts:
More people watch FAF than play - it is confusing when people change their names from what they are generally known as.
A lot of youtube comments on casts are people explaining the name changes of high rated players who are regularly casted; "TheWeakie is farms" etc. Perhaps that actually helps channel engagement but still.
I agree how much this should be allowed to constrict the people who actually play is debatable.
Perhaps some tooling to help casters manage the names of people in replays would help this issue. Something to view name history or a mod that will allow you to override display names based on the user id. I don't know how technically feasible that is @Jip
I like the "Nickname @Username" idea, it would be a good compromise.