It is. 90% of people familiar with this genre know it because of Sewer, Goreshit and others. You can call it "atmospheric-core" or "ethereal-core" or "new wave breakcore" or simply "sewerslvt-ish core", but it won't change a thing - it still will be called "breakcore", as simple as that. And "the real true breakcore" like Venetian Snares and others can be considered now simply as a type of this music subgenre. It's like those guys who claim that nothing anime-ish or visual novel-ish that is made outside of Japan is a real thing. Don't be like that, it's just shallow and all about the terms society is currently using.