I'm not interested in sea lioning. So I'll just ask for one specific claim that is false.
Anyone can take an existing Apache 2.0 project and change the license to AGPL 3.0. This does not require the approval of any prior contributor. Of course people can continue using versions released under Apache 2.0 under the terms of that license, but even then "approval of every single contributor" is irrelevant. See https://www.apache.org/licenses/GPL-compatibility.html
The situation where you do need the approval of past contributors is when you want to switch between incompatible licenses. For example, if they had previously released it as AGPL 3.0 and wanted to move to Apache 2.0.
(also not a lawyer)
No, you cannot. The very page you've linked to makes this clear:
> Apache 2 software can therefore be included in GPLv3 projects, because the GPLv3 license accepts our software into GPLv3 works
This is precisely what I've written. You can also apply the AGPLv3, you cannot remove the Apache 2.0. The contributions made under Apache 2.0, are still under Apache 2.0. The Apache 2.0 allows sub-licensing, so any contributor who uses those contributions from now is accepting them under the AGPLv3 and Apache 2.0. The former does not supplant the latter.
If we were to read this like a piece of computer code, the incompatibility would be mutual. GPL code does not permit further restrictions. "You cannot remove Apache 2.0" would be a further restriction. Ergo, you couldn't incorporate.
It's just that this isn't how you read or interpret legal text.
The linked page is correct. You can incorporate/sublicense Apache code into GPL code. You can't do the reverse.