The bare minimum for wearing any form of replica sports kit is that you at least actively participate in the sport.
So, cyclists wearing replica kit? Acceptable, seeing as they actually cycle.
Wendyball fans wearing replica shirts? Questionable, seeing as most just sit on their butts eating pies and drinking beer 🙂 and don’t actually play wendyball to any degree.
And how do swimming fans show their allegiance? I don’t remember ever seeing spectators at swimming events wearing trunks, swimming caps & goggles?
Do F1 fans watch the procession race wearing fire-proof overalls & helmets?
It must be pretty tricky spectating on skiing with all the crowd wearing replica skis.