If we’re committed to being an anti-racist and not just an ally (yes, there is a nuanced difference) then we have to make a conscious effort to unpack our own racism -- which can be really uncomfortable -- and remove the barriers we unconsciously put up when we're made aware that something we've said, done or shared is racist.
Sports team affiliation, much like political alliance, runs deep and strong within the American psyche. There can be such impassioned fidelity towards it that followers may be left blind to its imperfections.
The difficulty with identifying (and defeating) systemic racism, especially for those of us who are not its intended target, comes from the fact that its existence and implementation, by design, is insidious. Its invisibility ensures its longevity.