What, exactly, qualifies as being a "petty" reason, anyway? That seems to imply that there's some duty to buy 5(.5)e, and that you must therefore justify choosing not to--with some justifications thus being spiteful and mean-spirited.
I don't think it's either of those things, for example, to say that I would not buy 5.X because I think it has numerous bits of terrible mechanical design, that it actively fights against several of the explicit purposes for which it was made, that it outright flaunts or ignores the way actual humans behave and thus sets the stage for totally unnecessary problems by depending on assumptions of human (or player) behavior that are incorrect, and overall treats mechanics as an afterthought despite these being what actually constitutes playing the game.
Nor, for example, my belief that it merges the worst parts of design-by-committee (things that fail to meet an arbitrary and punitive popularity threshold are destroyed forever, never to be given a second chance; things that are popular are not necessarily things that are well-made) AND design by unregulated auteur (e.g. certain pet projects that lingered long after they should have been abandoned if the former standard were the only one; traditional elements preserved even though they're often literally less than useless). I don't consider that petty, any more than I would consider it "petty" to refuse to buy a car that I thought was badly engineered and designed with popularity and avant-garde style first rather than sound engineering, efficiency, and comfort first.