it might be that some football watchers watch players rather than teams, like tennis players, for instance. pre-1960 the only way to see a game was live. if a mega-famous player was appearing in or near your town, you'd go see them. bobby charlton talks about that frequently in his autobiography.
incidentally, my mentality when i watched city was the same as yours - i went to watch city. the opposition was totally irrelevant to me.
Tennis is a good analogy to the Murdoch League. It's football's equivalent of Wimbledon. No real home grown talent, but a roadshow of foreign talent stealing a wage from the international circus.