I think I should probably speak up, since I'm the creator of the mythology tag; I created it on the first day the site was in private beta while asking this question. Here's the thing: the word "myth" has two uses in English:
A pejorative usage, referring to "a widely held but false belief or idea"
A non-pejorative usage, "a traditional story, especially one concerning the early history of a people or explaining some natural or social phenomenon, and typically involving supernatural beings or events."
The word "mythology", however, only has one meaning and that's a meaning that's related to the non-pejorative usage of the word myth.
So when we tag a question about a Hindu story as mythology, we're not saying that the story is false or fictional. We're simply saying that the question concerns one of the "stories that are part of Hindu religious beliefs", as the tag description I wrote says.
And let me be clear: I think Hindu mythology is absolutely true. I don't think the stories found in Hindu scripture are fictional or metaphorical, I think they literally took place the way they're described. So by using the word "mythology" I am definitely not expressing any skepticism about whether our stories are true.
Concerning whether Mr. Alien should be blocked, I think there's only one punishment appropriate to everything he's done to the site: elect him as one of the permanent mods when we graduate out of public beta! Keep up the good work, Mr. Alien!