If you just clone the repo there will not be any sources from the AGPL:ed source within the project, only a text mentioning the name.
However if you build it locally, it will pull in the third party libraries. So as long as they aren't distributing any built packages without a AGPL-compatible license, I don't think they are doing anything wrong.
How did I not know this. How did I survive without this? Thanks OP.
Next time you decide to attempt Arch, you could try the included install script.
But for now I would also suggest starting out with something more simple, such as Linux Mint or Ubuntu LTS.
That's what I thought as well.
If you just clone the repo there will not be any sources from the AGPL:ed source within the project, only a text mentioning the name.
However if you build it locally, it will pull in the third party libraries. So as long as they aren't distributing any built packages without a AGPL-compatible license, I don't think they are doing anything wrong.
(IANAL)