Perhaps this is my interpretation, but I feel they are trying to convey the message that historical and ongoing police brutality against persons of color in the United States is more offensive than kneeling for the flag/anthem. The first step toward racial harmony isn't proving one's respect for the flag/anthem; it is to have those who are offended by the act of kneeling for the flag/anthem not only listen and understand the true message being conveyed, but to also join those who kneel in taking action to address the injustices lived and experienced by their fellow Americans of color. It is impossible to have racial harmony when one group's experiences is flatly denied or brushed aside by another.I don't think statements like this are helpful or will lead to racial harmony. Whether some of these young athletes recognize it or not, kneeling during the anthem is offensive to many people in this country. It's certainly their prerogative to do so, just don't expect everyone to approve.
When decisive action and direction is taken to make changes to the system and those changes result in significant reductions in incidence rates of police brutality, I imagine the kneeling will cease.
Just my two cents.