Why are there 2 forums?

Noob question but I live under a rock in bikini bottom.

ExampleThis: https://forum-en.guildwars2.com/forum/professions/warriorAnd This: https://en-forum.guildwars2.com/categories/warrior

I can't seem to post in the first one.

The first one is the old official forum which was discontinued shortly before PoF was released. They had to change it because the software it uses is obsolete and can't be updated and apparently it was only a matter of time before it stopped working.

It's still online so people can save or copy over any topics they want, but at some point it will go offline.

I think the old forum is now considered obsolete and supposedly will be taken down by the end of October? At least that's what I've heard, but didn't verify, as I don't use old forums, so don't quote me on that :P

I hope they keep the old posts archived - read only would be fine

From what I heard, these forums suppsoedly will be deleted at the end of October rather than just locked (as I said before, what I heard, but unverified to to lack of personal involvement). I've seen some people complain how they have to save all the relevant posts now and all due to that.