I understand and had considered it could be a misunderstanding, but it just wouldn't add up.
I think what's more likely than a total misunderstanding is, the player said something he thought of as a taunt but in reality was much worse than he intended it be. It may not have been racially motivated but I highly doubt Kamara would suggest racist content if there was none.
Perhaps the player insulted Kamara using racist terminology, with his point being the insult, but of course you just cannot use any racist terms.. eg the difference between calling someone a "cheat", vs a "(racist term) cheat"
At the end of the day, why would Kamara lie about it, and why would both Rangers players in ear shot react simultaneously.?