There are many what I call "Old guard" members on Flyertalk who believe an airline such as Spirit is unworthy of a real board to not only share mile awards info (worthless on Spirit) but general airline/fee info as well which all the forums do for all the "Traditional legacy" carriers. But even airlines such as Virgin America, Airtran which is dying, still have forums with no reasonable explanation given by Talkboard why for them and not Spirit. Let me say I am no fan of Spirit but I know they serve a purpose in the US air system though I despise their fees, you just have to know when you book what you are doing as I do fly them occasionally but pay only my airfare. I even book my tickets at the airport counter to bypass the online passenger usage fee. Average users would never know to do this but I'd tell them in a Spirit forum.
The bias I have seen on FT not only for this issue but others is pretty ridiculous and honestly it's one of the reasons why I don't come back nearly as often as I use to. Oh well.