I think there's a whole thing about happening to be born near a good football club, staying there, growing up a season ticket holder, watching quality football, then judging other people for supporting your club.
To give my United story: I grew up seeing my dad, who was born in Salford, every other week. He'd moved away from Manchester as a teenager but was obviously a United fan by then. Early in his career he moved further away still, met my mum, had children, got divorced and moved further away again. Obviously he didn't change his club allegiance upon any of these geographical moves. My mum wasn't going to take me to local football so sometimes, when something could be worked out that involved him still getting to see my sister and he could get tickets, he'd take me to United. Despite living hundreds of miles away, my first football match was United vs Wednesday in 1993. How could I ever turn back from that, even if I wanted to?
So we're in this place where I shouldn't support United because I grew up in the south and rarely got to go, so according to the Top Red Code should my dad have ditched United in favour of whatever team was closest to me if he wanted to take his son to football? Or should it have been the closest club to him, because he no longer lived anywhere near either Manchester or me? I was under the impression that you don't change clubs, whatever the circumstances? Should I have shunned my dad's offers to drive me to Manchester again and supported my local non-league team, despite not being able to go to any games because I was a child with nobody to take me?
As I grew up and started to go to games without my dad, I'd have to book days off work and expensive hotels and trains just to go to matches that weren't in high demand because those were the ones I could get tickets for. Was I not a true supporter?
I don't think that's even anywhere near a complicated life by today's standards. People move around. People watch the Premier League from all over the world. People have different commitments. There is no arbiter of who is and isn't a true fan of any club.
That's longer than I intended it to be and tbh a long justification of something I have no need to justify, but hopefully makes a point about modern lives and entitlement.