The challenge that Garrett will face is this. As soon as you bring up race in America it stops being about you and starts being about the white person. Let's say that Rudolph actually said it to him. Does it justify Garrett using a helmet to beat Rudolph? No. In fact no only does it not justify it, but Garrett actually ends up "losing" because Rudolph's real goal is to enraged Garrett (which surprise surprise, is what happened). But, here's the thing with a white person calling you an N-word. Unless you've been in that position before or have experienced that before, it is a creates a cascade of emotions you are completely unprepared to experience.
Someone calls you the N-word in that context and you'll start thinking about all the racist shyt this country has done to Black people. And you know that they are invoking the power dynamics of that past to put you in your place. Now I'm not going to say that this is the only thing that could have set Garrett off, but there definitely aren't many things and this is one of them. Sadly any nuance discussion about how race played a role in this interaction will be subverted because our Country is racially immature. There is racism all around us and African-Americans are basically second class citizens but people lose there mind if one Black person says that a white person called them an N-word.
But if you're Black, you live in America and you're reading this, this is what I'll say. There is a very high likelihood that at some point in your life, you are going to be on the end of some racial shyt like this. You don't have to believe Myles Garrett, but at the very least, take notice of the people who get angry about his allegations instead of wanting to get to the truth. Because one day you might find in a Myles Garrett esque situation. Whether it be a racist co-worker, a racist bank, a racist teacher, a racist police officer and that racist will know how to game the system and make you look crazy knowing all the while that there racism is what set you off in the first place. You don't have to be Myles, but you should demand that the truth come out. And you should look skeptically at any person who doesn't want to know the truth because at some point you might be the person people are calling "crazy."