If they are not part of the main document, I should be able to simply remove them. But that's not the case, the invariant sections are a very strong part of the document. So strong that you can't even remove them. It's even more important than other sections of the documents, because those sections can just be removed.
Is it the non-removal bit that you object to now, or is it the verbatim bit? Or both? You keep jumping from one topic to another.
So that they aren't part of the document is just nonsense.
I didn't say that, I said the _main_ document.
It's like saying you can edit a whole program, except two source files which do something different than the rest of the program.
Now you changed the topic, once again. Either we are talking about source code, or documentation. We cannot speak about both, since they are different. There is no point in not being allowed to change source code, hence why you should have the right to change it.
There is a perfectly valid reason in not changing a non-functional work, like my memoirs, or your toughts about how much you love butterflies. You shouldn't be able to change what I or you thought about an issue.
There is also a perfectly valid reason in having invariant sections in a document, I might have written a document about how you twiddle frobs in a black box, and wish to give a note to everyone that my (non-existent) wife baked me cookies when I wrote the book and how much it helped me, and include a recipe for these cookies. I also don't want to have someone modify the recipe to produce something horrible so that everyone will think that my wife can't cook.
I also might want to make this note to my wife non-removable, since the book would not have been possible without her support.
For documentation, all this makes sense, for source code it does not.
One can agree that not being able to remove the invariant sections can be a bit troublesome if you have 1000 people who add such sections, each adding their own anecdote about how much they loved (or hated) my wife's cookies.
To me the GFDL has other problems, namely, it being a overall complex document, far to complex to be grasped in the same way that the GNU GPL can be grasped. If the GFDL has invariant sections, or not, is frankly a side issue which everyone seems to miss.
There is just no reason to accept such a restriction.
Just because you cannot see the need for such a `restriction' doesn't mean that there are good reasons to protect ones freedom to have it.