While you are granting the FSF the ability to relicense your code, they only have the ability to re-license your existing code. As it is already under the current version of the license, if you do not like the new version, you can simply stop using it for future additions. If I license something under "GPLv2 or later", and the FSF releases GPLv3 that is the SSPL, I can simply keep using my existing code under GPLv2. If the FSF releases GPLv3 and it is CC0, then I can once again keep using my code under GPLv2. In either of these cases, I don't have use the new version of the license on new versions of the software. While the existing software is always "GPLv2 or later", later additions can be "GPLv2 only".
An "or later" license allows for making my license compatible with future versions of the GPL. Personally, I see this as a good thing.