This has absolutely nothing to do with how pointless the anthem is at sporting events. The fact that people stood doesn’t make it any less pointless
If it was pointless they were free to ignore it. Most didnt. I suspect because many liked the opportunity to reflect on where they live and why their way of life is possible. Perhaps they were there with an uncle or dad that served. Or perhaps they were missing an uncle, dad, brother, etc. that served and are no longer here.
Nonetheless, people were free to not participate, to believe it was a stupid and nonsensical misplaced event. The overwhelming majority did not share that view. But keep hoping.