To each his own. I have no AFL club allegiances so I get to enjoy every game regardless of who wins and get to fully appreciate and acknowledge good play and skills from both sides. On the other hand one of the section's stalwarts, Shifty, has been a Blues supporter for donkeys years, yet when he moved up to Qld he added a Suns membership &now supports 2 teams. Again, to each his own....
I do, I support the Swans and also like Richmond
To me, you can only be a supporter of one team. If you do the scenario you describe, you are not a supporter but a sympathiser of those teams. I realise everyone is not like me, I'm a carlton supporter and I see all other teams as the enemy because I believe that rivalry culture makes sport stronger. But even if you like other teams, you should only have one that you declare yourself a supporter of.