I really like this manga, proof that you can have a survival-slice of life "post-apocalyptic" story, without having to be centered around war or conflict.
But that would be ignoring context. Style of speaking is one of the determining characteristics of a character. You can tell if a person is spoiled, annoying, disgusting or other simply from the way they speak. Your preference doesn't matter, it's the author who decides how they speak and the translator is just doing their jobs of translating in the most accurate way as possible. After all, it would be pretty boring if everyone speaks the same way.