Saints players and other key sports and public figures are angry at Drew Brees for his anthem comments

The National Anthem is a patriotic song that symbolizes America’s core value: freedom. Therefore, it’s important for men and women to know the rules established under US Code 301 for showing respect in conduct when it is performed.
Proper Anthem Protocol Order for Civilians
(military personnel see this)

Stand
Before the National Anthem begins, crowds will usually be asked to stand. Why stand? It is a sign of appreciation for our nation and its core values. Is standing for the National Anthem a law? No, it is not mandatory. But Americans owe a great debt to those who have paid the ultimate price to win and protect our freedom, which is why it’s important to follow proper etiquette and stand for the Anthem. The entire Anthem should only last for a couple of minutes, so standing isn’t going to leave you “winded.”
Face the Flag
Many people assume that they should face the person who is singing the National Anthem, but this isn’t necessarily true. If there’s an American Flag being displayed — and there usually is — you should face it instead. If there is not a flag on display, you should face the person whom is singing the National Anthem, giving them your full attention.
Remove Your Hat
If you are wearing a hat, you should remove it for the duration of the National Anthem (unless it’s being worn for religious purposes). This tradition goes back more than a century, a time when wearing a hat indoors was considered rude.
Place Right Hand Over Your Heart
Next, place your right hand over your heart. Assuming you are wearing a hat, remove it with your right hand and place it over your heart.
What About Military Service Men and Women?
Military service men and women should perform the military salute at the beginning of the National Anthem, holding this posture until the end.
That concludes the steps you need to do to show respect when the national anthem is played.
Did You Know?
Here’s a fun fact that not many people know: the Star Spangled Banner had been around for 75 years before it became the National Anthem. It wasn’t until 1889 when Secretary of the Navy Benjamin F. Tracy signed an order to make the Star Spangled Banner the official tune for raising the American flag. Fast forward to 1916 and President Woodrow Wilson declared the Star Spangled Banner to be played at military events and other occasions as well.
"The National Anthem is a patriotic song that symbolizes America’s core value: freedom."

A country isn't free if a portion of its population is being discriminated against by law officers that are paid to protect them. Until those people are treated equally, the gesture of standing during the anthem is an empty one.