They created it that length for their reasons. You might want it a different length for your reasons. It's not clear that their reasons trump your reasons, given that your modification has no effect on them whatsoever.
I choose to listen to songs by an artist because I enjoy the choices that artist made.
That's fine.
Other people make other choices.
That’s fine, as long as you have obtained permission from the copyright holder to create a derivative work. Otherwise, their reasons very much do trump your reasons.
Sharing a derivative work could breach copyright, but if you are doing it for yourself you don't need permission.