Narrow-minded individuals, that can not wrap their minds around multi-threaded complex issues, and insist that all issues meet simple "Black -vs- White" parameters.
Wiki is not such a narrow-minded venue, and thus one will encounter things from multiple places and disciplines while participating here, and it may not always be readily clear as to the where and the why these things are here. So, do not run around deleting things that you do not understand, purely because you can not fathom the where and the why (WikiPuppy behavior).
See: WikiIsNotWikipedia