Why do some people support teams located as far as Seoul is from Daegu?

Are they supporting them just because they call it their home territory?
In a way, it's like playing highlights of a Seoul team in Daegu
and saying, "These guys are our team."
Honestly, if the distance is around 320km, wouldn't it be better
to just start a professional team instead?
Whether it's football or baseball, the distance is almost like Seoul to Daegu, so I'm asking because I find it fascinating that they support Seoul teams claiming them as their home base.