Firstly, the systematic racism is the oppression of the minority race oppression perpetuated by societal and hierarchical systems in place, run and dominated by the majority race. In the west, white people are the vast majority, which makes people of colour the minority. You simply cannot deny that the minority cannot oppress the vast majority. Not only is that not possible in the theoretical sense, if you look at reality, and the racism that is currently the subject of conversation, oppression of white people is not happening and hasn't happened. That doesn't mean that white people aren't subject to racial verbal abuse, but if you're talking about oppression, the statement you have in quotes is correct. It's true, not all white people are intentionally oppressing people of colour, but the idea is that the racism (oppression), which has been running deep for longer than any one person has been alive, has developed and seeped into every aspect of life to the point that now even the inaction of individuals in the face of oppression and their privilege which stems from such system is an indirect contribution to the oppression, and the aforementioned oppressing systems in place run autonomously.
The issue is that I don't think you have a clear picture of what oppression is or have a grasp of indirect contribution to oppression. e.g. Assuming you're white from the statement you made about being called a 'white boy', you benefit from the privilege of having a lower chance of being stop and searched by police based simply off of assumption. Yet, if you saw this happen to a black person (who is statistically more likely to be subject to this) and you considered there to be a lack of reasonable grounds for the police to carry this search out, and you didn't speak up or at the very least question the nature of the stop and search, that is you benefiting from that privilege and indirectly oppressing. It's unfortunate, because you didn't choose to be privileged, yet you bear a responsibility to those who aren't as privileged due to the system that you benefit from, but that black person who got stopped and searched simply because they are black also didn't choose to be on the opposite end of that privilege.
You could argue that this is a result of a relatively high knife crime rate in statistically more black neighbourhoods, but again, if you think deeper you could perhaps suggest that this is the result of a much higher % of black people in poverty resulting from reduced economic and societal opportunities, which came from increased oppression of people of colour the further back in modern history you look, which led to the development of 'hoods' and thus is a direct, chain-reaction consequence of oppression - if you took this perspective, you could say that racism is just as rampant as it has ever been, it's just modernised. Instead of white people lynching black people, it's black people killing black people as a result of the conditions they were forced into by white people. Being in a position of privilege it's hard to see this, so it would be unjust to blame everyone of it, but it's important to understand the difference between what a white person might experience in western society to what a black person will.
Again, racist abuse against white people is ENTIRELY real, but oppression maybe not. I think the anger response of some white people to the current movement is that the narrative suggests that all white people are directly to blame which might make you feel accused and attacked, which is understandable and should be corrected.
Also, why do you assume that people think it's fine to be called a 'white boy' but not a 'black boy'? I don't think many people would agree with your statement.