Sports fans are idiots. Why do they even like the teams they do?
- Because the teams claim to represent the city the fan is from
or
- Because they win.
or even
- Because they see them on TV a lot (this can be a subset of the first one)
These are the sorts of a reasons a dog might provide for why it likes things.
You forgot a big one, and that's being raised that way. All the non-soccer teams I'm a fan of are because those were the teams my dad liked so I grew up watching them. Until extremely recently the only non-insane reason to be a Browns fan was because you'd been born into it.
Acceptable reasons for picking a team:
-geographically closest team
-team from an area you used to live in
-some specifically personal connection ie: My grandpa is a Montreal Canadiens fan despite never having lived in Quebec because when he first immigrated some French-Canadian co-workers helped him integrate into Canada and he ended up following their team.
-family tradition (though only acceptable if historical reason for family tradition is one of the above conditions)
Unacceptable reason:
-picking a team solely because they're really good at the time
Switching teams is only acceptable if you move and switch to the new geographical choice, a relative/close friend starts playing for a team, or the team relocates away from you. Switching to whatever team is currently good is the mortal sin of sports fandom. And if you live somewhere with multiple teams like New York you can't flip-flop. You to have to pick one team per sport and stick with them.
So until essentially this off-season I can't imagine anyone being a Cleveland Browns fan without following the acceptable reasons for fandom.