There's a contemporary aesthetic that insists serious fiction should be a sort of heightened journalism, that the way to relevance and truth is through a rigorous presentation of things as they are observed to behave in the corporeal realm. The term “gothic” is vague enough to include a lot of things but certainly not that. The word itself seems to rush to and agitate some center of the brain in a way that cocaine (or, at the very least, sugar) might - not a very journalistic way to go unless you fix on the case of Hunter S. Thompson.
The word is so loaded because writers like Radcliffe, LeFanu, and Bram Stoker tapped into something that matters. This something may not have much to do with the corporeal realm but nonetheless has a lot to do with how the human mind goes about its business, how it finds itself pulled by the gravity of its own dense irrational core.
The relevance of the supernatural in the stories of writers whose obsessions go beyond plot exposition is not that these manifestations represent what actually exists but precisely that they represent what does not exist. They are familiar in discomforting ways, but they refuse to be rationalized even when Ann Radcliffe herself attempts to do just that. They are the unknown bearing down upon us.