That’s a pretty archaic view of football. Yes it’s natural that as the game emerged the bigger teams were the ones to attract the imaginations of foreign countries, which is why certain team names resound all over the world.(in every sport or indivudual sport) Man united, Barcelona, Real Madrid, Liverpool, Bayern Munich, ac Milan, inter Milan etc.
There are rare occasions when for whatever reason a smaller club will have one of these bizarre fan bases like the phillipines stoke city fan club but largely, the established clubs will always reach a wider fan base. This is not to encourage some sort of old boys club and several teams in recent years have threatened to upset the apple cart. Tottenham are becoming more and more popular, Arsenal were massively popular and remain to be especially after their emergence with wenger in the 90s (they also had lots of history which helps), but their success was achieved organically. Leicester city had the entire world rooting for them in recent years, unfortunately they basically got dismantled and the romance died with it but had it not I’m sure their fan base would grow globally too.
Football is the most global sport in the world, and the premier league is hugely popular. Because a fan loves overseas does not mean he or she is any less connected to a club than some guy who lives in Salford and moans about mourinho on line all day. That’s what sport is about and despite footballs continued selling out to money and commercialism some people are still massively bound to a club for romantic reasons and can support them passionately from anywhere in the world. I’m not from Manchester but I grew up loving them, I’ve been a season ticket holder and will be again when I return from working in a part of the world that I wake up at 4am to watch and never miss a game. In fact, few things in life are important to me as man united. But I’m not from Manchester so I have no right?
Football fans are absolutely entitled to be indignant about first, the manner of city’s emergence and more recently the manner of how they have responded to success. They are a small time petty club without class, who happen to play good football at the moment. This football though -does not outweigh their toxic role in the modern game. So go on, watch their documentary and eat it up- it’s what they’re paying for. But I’d hold back on lecturing a person you don’t know about the limits of his or her capacity to support a club.