The problem isn't grouping people that are similar, whether culturally or otherwise. The problem is assuming similarity based on race. To say L.A. girls have a similar style and look, for example, is a specific claim about customs in a particular area (though we'd have to specify things like socio-economic class, geography, networks, and maybe cultural dispositions to get an accurate idea of who you're talking about). To say black women are the same doesn't give much attention to any of these details and instead just says skin color is the primary predictor of certain behaviors. This is the same premise that literally all racism is built on, especially scientific racism in its various iterations over the decades.
Below you post, "you're going to get Nigel upset," which tells me that you think that matters of race and racism are emotional responses at the core and that it's about intention and meaning. Similarly you mention "shaming" for "making observations." What I'm explaining to you is that racism is very basic. It's not about how anyone feels. It has a simple definition, which is using skin color or ethnic origin to explain anything. "Simple observations" and "common sense" are laden with whatever frame history has provided us. There is such a thing as culture, and arguably even some cultural similarities that people with the same skin color or ethnicity share due to specific historical circumstances. It's doubtful that the way they love or have sex with people could be one of them. To put it bluntly, there is no special black cocksucking class people receive from their parents. There is also no disposition to be entitled or crazy, as some others have posted, simply because of one's place of birth or racial background. Those are equal opportunity characteristics. In my view, you shouldn't be so sensitive to criticism when you're posting in a thread created by one of the site's arch-trolls specifically to incite problematic posts.