If I see an ad for car mats, do I need a disclaimer that the car doesn't come with it? If you buy a bathing suit, does the model come with it? Sometimes you need a prop to make the product visually meaningful or appealing. But it ends there. And if you make the mistake of thinking something else was included and you are corrected, just shut up.
I can't easily categorize these people because they behave this way for unknown or endless reasons. They may have hit a rough patch in their life, are angry, ill, lonely, or maybe not getting it often enough. Maybe they do it for sport; if they complain often and loud enough, there is likely an apology and some concession gift that most companies will surrender to make the problem go away. And with social media and on-line reviews, everyone has the potential of being heard, regardless of how unreasonable their complaint is. And companies don't want that. So we must continue to suffer with the obvious not for the benefit of the idiots but to temper the assholes.