Earlier quoted context omitted.
> Banning all Russian athletes is a clear decision. Yes, it would be clear if you define "Russian". Do you mean everyone who currently holds a Russian passport? Everyone who has at some point held a Russian passport? What about someone who used to have a Soviet passport with their nationality recorded in it as "Russian" but who didn't live in Russia? What about people who used to have a Soviet passport and lived in R…
Any chess players who played under the Russian flag before the invasion. I don't know the exact details in chess, but in most sports you have to declare a country when participating in top level sports. For example dual citizens cannot just switch between playing for any country's national team that they are a citizen of.
(You might think of having a rule that you can only change your "sports" nationality if you "renounce" your previous citizenship, but it many cases it's not possible to "renounce" citizenship: you can let your passport expire, but whatever condition, such as place of birth, allowed you to apply for that passport in the first place would still exist so you would continue to have the option of receiving a passport for the previous country if you ever wanted to apply for one. Moreover, it would be impossible for you to prove you hadn't done that because countries do not, as a rule, issue documents to certify that a given person does not have a valid passport!)