@arya That's the GPLv3, please don't say "GPL" when you mean GPLv3.
The reason why that is written is because otherwise people would just go edit the GPLv3 and add proprietary terms and say that such is the: "GNU General Public License Version 3".
The FSF does permit editing the GPLv3 into whatever license you want as long as you remove all mentions of GNU and the FSF and remove the Preamble - but it's a terrible idea to do that, as in almost all cases it would be better to add an exception under section 7.
@iska Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
@arya MIT has many licenses, did you mean the expat license?
I'm not aware of any trademark on "MIT License", so you can go name a license you have written that if you want to, but that will be very confusing.
The expat license text is copyrighted (the lack of a verbatim copying permission sentence is yet another issue with expat, but at the same time that doesn't make it not copyrighted) but at the same time is quite short.
Arguably most sentences are not original or creative as they are the only way to write X thing and so if you were to start changing the sentences until the license looked completely different, you could claim fair use over anything that is derivative.