^Okay, then the reason you're not making sense is that you're dead wrong in your core assumptions. It's not "ignorance" to acknowledge that there are no sharp dividing lines between science fiction, fantasy, horror, and other facets of speculative fiction. As Greg pointed out above, there's a wealth of literature that includes aspects of two or more of those genres. That has nothing to do with the ignorance of the masses; it's about the free choice of creators to go wherever their imaginations take them rather than being shackled by simpleminded assumptions about categories. If anything, it's ignorant to assume the genres don't
(And for the record, "some guy" was right.
It's arbitrary to insist a century has to begin in a year starting with 1. Yeah, there was no "year 0," but there wasn't a "year 1" either -- or a year 10 or a year 100 or a year 500. The calendar we use wasn't invented until the sixth century and it was based on an incorrect assumption about the birthdate of Jesus Christ. So it's all completely arbitrary to begin with, not representing any kind of cosmic truth. A calendar is simply a convenience adopted by human society, so if the mass of humanity agrees that a century begins on a certain year, then it's foolish prescriptivism to disagree, to sacrifice clarity in the name of pointless purism.)