The AGPL is not the issue. The CLA is. It allows the project to change licenses at will, without going back to all contributors and asking for approval.
I mean I dislike CLAs personally, but I understand why they can be healthy for a project growth.
The last time I saw a FSF CLA, it was part of a larger agreement that also imposed obligations on the FSF.
In the long run, there may be risks to the FSF holding so many copyrights. But I don't think it clarifies matters to treat the FSF's CLAs the same as ones used by a "open core" VC funded startup.
Especially when the for-profit company openly announces this assignment of rights is for the purpose of selling code you wrote to others without giving back to the authors.
The FSF doesn't have a track record of asking for CLAs, and then selling your code to others under different licenses and pocketing the profits.
These two things are being conflated in this discussion. One thing is a CLA and copyright/license changes. The other is the license itself.
Source: My PR was merged in 2021, the changes are still part of Synapse, and I never signed any CLA. I don't think they'd be able to get enough sign-offs from historical contributors to pull off any actual shenanigans with the Synapse license.