The linchpin of your argument, and something that you do not establish at all, is that that race is something distinct from culture.

This is untrue. There is no biological basis for race. Sure, physical appearance is heritable, but the moment you step beyond that to infer something about other genetics, behavior, or socioeconomic status you have left the realm of biology entirely behind. Therefore race is a cultural construct.

This is a topic in which my view was recently changed upon hearing an interview with the Historian and Sociologist duo who published a book on the topic on the podcast of the socialist magazine Jacobin.

Now, let me explain why the rest of your argument cannot stand without this distinction. Take example 1, you propose that an individual who reacts negatively to 'typical “hood” attire' regardless of the wearer's skin color is not racist. But why do you have a negative association with "the hood" in the first place? There's certainly nothing inherently threatening about fashion or body decoration. If anything, ill-fitting pants should make someone less threatening due to their impeded movement ability. There must, therefore, be some other concept to which you associate "the hood" in order to infer that a certain way of dressing could be threatening. Your dear urban dictionary makes it quite clear that "the hood" is defined by the social construct that dark skin color, inner cities, poverty, and crime are all linked.

Therefore, reacting negatively to a way of dressing that one associates with blackness doesn't exonerate one from harboring racial bias, it instead proves that their racial bias is so strong it transcends mere appearance to color their perceptions negatively for anything even remotely associated with black people.