People take the Trick Ending, a non-canon ending which was made by the author just to appease the readers that didn't like the magic stuff and it's a literal middle-finger to the entire story, characters, and it's themes (and to the audience too), to mean that magic isn't real period when that's extremely easily debunkable. But those are the people that at least read some of Umineko.
The others, like Michael Julius (which you likely know from ComicVine) are literally making shit up based on fan theories already disproved by the story itself (all of Umineko is Lambda's dream, which is so LMFAO if you had actually read the story), or are literally misinterpreting scans to mean what they want to mean (ex: someone to me said that a scan that was talking about waiting for the police to arrive and ideantify the culprit actually means that the Witches were fearing the police and their guns, i.e. human guns > witches).