Well I have wasted time making your post family friendly, but I have no idea what exactly the issue is. Other that the word SPAM. So I will give you a link to general information on the junk mail control in Thunderbird http://kb.mozillazine.org/Junk_Mail_Controls

SO like, whats the purpose of spam and junk folders along with wtv if anything goes into the actual inbox? Although I suspect that the spam folder in thunderbird holds what literally were marked as spam, rather than a good portion of 17k of mail in inbox.

I got a bunch of other mailboxes forwarding to this account, that from what I remember are called labels.

Did you read that link? It explains in some detail how Thunderbird junk mail filters work. Explains that Thunderbird uses the term Junk not spam. So anything using the folder name of term SPAM is not something controlled by Thunderbird.

I am guessing again. I assume WTV mean whatever, not the Perth television station. http://www.wtvperth.com.au/about

I am also assuming it is a gmail account from the use of Labels. They are the only ones I know of that use that term.

If it is gmail I suggest you read this. https://support.mozilla.org/en-US/kb/thunderbird-and-gmail It discussed the peculiarities of gmail and it's non standard approach to IMAP.

I'm not inclined to begin filtering out all of the spam that i've accumulated over a decade in order for thunderbird to pick it up again. I was trying to get at the fact the thunderbird maybe should look at the official term of gmail and look at that folder "spam" in order to pick up on that?

You are connected to Google sever using I assume IMAP.

IMAP is defined here. https://tools.ietf.org/html/rfc3501 and in the updated by links.

I am not aware of anything in the IMAP protocol that talks about SPAM or SPAM flags. Perhaps you can prove me wrong. For to make any sort of SPAM link. The RFC has to be followed. I would love to put it to the council and the developers. But we do not get to redefine the RFC's for mail any more than we have influence over the RFC's for web pages. We implement the standard.