AITAH because my friend wants me to cut off a friend due to them using the N word ( both not black )

Ok so me and my two friends got to know each other over discord , we know each other for a long while ( 9 months over discord ) .

All of us are non blacks and the three of us are not racist at all , in fact our race gets racially slurred sometimes but that’s not the point.

Anyways yesterday one of the friends ( let’s call them M and the other one K ) comes to me saying that K wants to cut them off because they ( M ) said the N word .

I do know that K is definitely not a racist and they used the word like that , theystarted apologizing to M right after they said it made them upset , K wrote a medium length message apologizing sincerely but still M wasn’t able to forgive them .

I do understand M’s point and totally get why they want to end the friendship , and I do know K is not a racist but it is still so wrong to say that word even if you don’t actually hate black people .

So I told K that i understood M’s viewpoint and I don’t see anything wrong with it but they still think it was too harsh to cut the friendship because they are not racist considering how good of friends they were.

Now M wants me to end the relationship with K too unless I want to face the same fate💀 what should I do