They don't have ownership, but it's disingenuous at best to pretend that they don't have a strong association with them based on their politcal and religous leanings.
I'm in the camp that finds them cringe worthy and pointless. I don't see the need to wave any national flags at a domestic competition (even the Saltires).
However, I'm certainly not pro-censorship, so I wouldn't want to prevent anyone from displaying whatever they like.