Why is kneeling for anthem seen as a sign of disrespect?

I’m having a hard time understanding all the people who are so upset about someone (various athletes) bending a knee when the national anthem is played or sung. When did going down on a knee become disrespectful? What do we do when we pray? What do Catholics do when they enter the church before seating themselves or leaving? What do you do when you are in emotional pain? You go down on your knees.

Showing the flag disrespect is turning your back on it or burning it — but it’s your right to do either. I think that people are so consumed by negativity and complaining that they’re making the bending of a knee a negative statement. My first thought was that the players were showing respect and praying for a better, more united America.