I think there are people who totally back the drive to end racism that can find taking the knee uncomfortable.
For some, it is associated with Feudalism. My MIL worked in service and was expected to 'know her place' - the accepted face of class-division that had its roots in Feudalism. There are those that argue that we are in danger of returning to such times in some parts of the world.
www.researchgate.net/post/Is-the-feudal-era-returning-And-what-can-we-do-about-it
Or indeed that it is re-emerging in the name of neo-feudalism:
en.wikipedia.org/wiki/Neo-feudalism
There are Catholics who object to it as they see it as similar to genuflection, something reserved for humility before God, not man.
I have no wish to prevent anyone protesting however they like, but please let's not assume that anyone who feels uncomfortable with the nature of the gesture does so purely for racist reasons. Nobody owns the gesture, since it has been used during history by different groups to mean different things, but people who have already ascribed one meaning to it will have a visceral reaction to the gesture itself.
Since we all want equality for all, a gesture which suggests servility or religious humility to some might not be universally effective. Of course, it is the right of those who use it to do so, but at the end of the day we all want equality not more division. I've seen several people suggest that teams standing arms linked would give an unmistakable message of unity. I'm not interested in telling others what to do, but we can at least look at why the message might be failing some.