The debate about the National Anthem at sporting events

Do you think that the debate about the National Anthem at sporting events like NFL football games is at it's root a debate about race as some suggests? Is it disrespectful in your opinion to not stand (or to kneel) for the anthem or is it a legitimate and respectful way to bring attention to racial or systemic violence? Furthermore should players be required to stand for the anthem or is this a violation of free speech in your opinion?