But you are doing the same as what you are complaining about.
Racism is a complex phenomenon not limited to the simplistic view "they don't like black people". This representation is doing a disservice when some truly racist people are then justifying their actions and beliefs by saying "I cannot be racist, I'm friend with the garbage man who is black: he is a good black man, is polite to me and stay at his place. So, if I'm not racist, what I'm doing is just legitimate".
In the context of Tulsa, it is difficult to believe that the frustration of racist people seeing black people more successful than them has not contributed to the situation. It seems very natural and logical (and that's even the core of "white supremacy": it clearly states that white people deserve a better position in the social hierarchy than black people: white supremacy framing is all about how some classes are reserved to white people and not black people), and if you are claiming that it is not the case, you are the one with the burden of the proof.
While you have a point on raising that racism should not be reduced to only a class issue, you should have raised that as a precision around the discussion instead of presenting it as if racism has absolutely nothing to do with class and class sentiment.
To take back your parallel, what you do can be seen as:
"A person entered a bar and was raped" (what you say)
vs
"A woman entered a bar and was raped". While nobody here claims that men cannot be raped, there is social phenomenon that create a gender imbalance, and it is important to not reduce the situation to "it has nothing to do with gender and the social norms around it".
In the rest of your comment, you, yourself, are doing a lot of interpretations. The fact that someone noticed that a class factor may have had an impact does not mean that they or all readers will conclude that it is the only way racism can happen (that is a huge stretch: if they know what happened at Tulsa, they very probably know a lot of other cases where the "only due to class" theory does not hold up).
Same for "victim blaming": the fact that they were successful were obviously not used to excuse the massacre or pretend that somehow it was the black people's fault, the context is clearly to condemn the white racist people (and the success of the black people seems to be presented as an obvious additional factor on the racists, as it is obviously unfair to pretend that some people don't have the right to be successful).
I think the first comment was not totally perfect and would have been 100% fine if they would have simply added "class was one of the factor". But I think your reaction has way more problems and does a bigger disservice by reducing racism to a framework that can easily be instrumentalised by real racist people.