This entire anthem protest thing is a form of self-destruction, typical infantile-rage seen in very young children/immature people. The NFL cannot continue to sustain major losses of revenue and disruption of its operations without negative impact on the players' bottom line.
Often in infants, not getting something that they want strongly triggers a feeling in them of anger and a desire to see the entire universe, (including themselves) destroyed. For infants, this passes as they grow older and is replaced by a healthy ability to channel and restrain rage-impulses.
Much of the basis for infantile rage takes place on an unconscious or semi-conscious level and so is too subtle for a person of low intellect (or immature intellect) to detect.
Their desire to have their infantile rage gratified SEEMS reasonable to them because emotionally-centered infants/adults only need strong FEELINGS / INTUITIONS to believe something is correct, not logical reasons which may be explained rationally.