Well, I respectfully disagree back.  Racial and ethnic slurs can be prosecuted as crimes depending on their expression.  There are laws that prohibit hate speech and harassment, but there are no laws that prohibit kneeling during the anthem.  It is the law, not personal opinion that determines whether the two cases are the same in connection with free speech.  If speech can be prosecuted, then it doesn't qualify as "free speech."  If speech can be prosecuted it is either more or less than free speech, but it cannot be just free speech.   The fact that racial slurs can be and usually are some kind of prosecutable crime, but kneeling during the anthem is not, makes them different.