it's existing on the screen, where you can see it, and where people can interact with it. it has a voice, mannerisms, etc.
it's not that big of a mystery that the new possibilities that have been opened up by this new medium might lead some people to feel they belong more there than in meatspace.
it's seems like the virtual version of putting on a fursuit and going to a con. no one is forced to watch/listen/interact with her, but if they do it seems evident to use the requested pronouns, etc.
(and I'm not talking about this meta-discussion of whether Lina is animated by Marcan, but even in this case, to me it seems common sense courtesy to treat Lina as her; like a character in a book, who might have different intentions than the author.)
