>Braixen's name in Japanese is テールナー (Teerunaa)
>One of the nice things about kana is that, unlike in English, you don't have to memorize an absurdly large number of arbitrary pronunciations
>Whether in hiragana or katakana, a テ not followed by an ァ, ィ, etc. is always pronounced te, ル is always pronounced ru, and so on

So why is Teerunaa heavily misspelled as Tairenar on Bulbapedia? The "ar" at the end is easy to understand; that's just how Japanese to English transliteration works for elongated "a" sounds in many cases. But that doesn't explain the "tai" or the "re." Bulbapedia's talk page for pokemon info boxes tells us that that field is for the "Japanese name of the Pokémon, official romanization." But what are the sources for these official romanizations?

More importantly, why use them when they're obviously wrong? If someone draws a picture of an anatomically correct giraffe, gives it the colors of a giraffe, draws a human standing next to it for scale, writes its scientific name beside it, titles the picture Giraffe, then tells you "This is a picture of a car," why should you pretend that they're right? Being the source of something doesn't automatically make a person right about what they say about it.

TL;DR I guess what I'm trying to say is: if Bulbapedia demanded that you start referring to rice balls as jelly-filled doughnuts, would you do it?