The examples you're giving are not helpful because they are clearly designed to be bad. Lightsabers like croquet mallets doesn't sound good (although if someone wanted it, then so be it), but maybe, say, a Phantom Menace without Jar-jar doesn't sound so bad, and in fact such a thing does exist as a fan edit, as you probably know, and many people hold it superior to the original.
But anyway, comparing game mods to literature or movie mods isn't exactly a well-fitting analogy because in games, unlike movies or books, the gamer is already 'modding' the experience in a sense just by playing it. When you play Half Life and murder the first security guard you see to take his gun, that's a mod. When you exploit an AI weakness to make a boss battle easier, that's a mod. You are 'modifying' the creator's vision of how the game is 'supposed' to be played. Now when it comes to open-world games where there are already more ways to play than a creator could envisage, modding is almost a natural extension of the game design: the game is already being 'authored' by the player as they play it, and no two player experiences are going to be alike. So why not mod it, then? That's just adding your own imagination to what the developers gave you, and becoming part of the creative process. That's less insulting to the developers and more of a tribute to them, if you think about it. They made this awesome world with all this potential, and inspired you to join in the creative process with them to make something that even they did not envisage.
Personally I'm not fussed about using mods because I'm mostly a console player and I also like to experience the game as the devs intended it. But if other people mod and get satisfaction from it, then that's cool and I like seeing what they come up with. Gaming still doesn't really have an established auteur theory like cinema does, and when something is produced by many dozens of people in a development house anyway, it's authorship is already a complex question even before the modders get their hands on it. It's all part of the evolution of the form, and to bar that evolution by invoking the standards and norms of another art form (cinema, say) is illogical, unnatural and stifling.