It is not his opinion that has been punished but an act of what they see as an insult by his salute.I cannot see it any other way. I am not sure whether our own FA is partially funded by the government at a guess I would say not. The decision to ban him certainly was not political. A very old gentleman seemed to think that in this country around the late thirties early forties a law was introduced and passed banning Nazi Salutes in this country. (The time of Mosley and his hench men) I do not know if he is correct but I do know that to be the case in other countries.
Nazi salutes are illegal in Germany, Austria, and France, and some other European countries, but not in Britain.
No it's not. The mere act of receiving government funds does not make whatever the FA does a government action. They are in this case acting as a private employer. You still have to consider that it is only "opression" if he is being denied fundamental rights available to other citizens because of his viewpoint. Representing the FA in a football tournament is not a fundamental right. He's being given every right that every private citizen has. He can say what he likes, but his employer doesn't have to like it and can fire him for expressing views contrary to theirs. You can argue against the FA's policy and that they should be more tolerant else the citizens of Greece should vote to withhold their tax dollars from the FA. But you can't make any sort of meaningful argument that this player is being oppressed.