Because for most male football players national team pay is not their main pay. At least the ones who are good.

Nope, that is not true. Government can’t interfere in running of the local governing body. Even that is not black and white. Government sponsoring a team will not be a problem at all.

Also, people aren’t celebrating because the team is state sponsored. They are celebrating because the government was surely going to exploit any success. Happens in every country to some extent. Sports success creates goodwill for the government. Iranian government was going to actively try to gain goodwill out of it.

Finally the players themselves have made statements supporting the protests. They are with the people. In first match they even refused to sing the national anthem.