Why should they make and sell left-handed items? Because there are left-handed people that will buy and use them. I think you're mistaking what privilege is. Privilege denotes the advantages afforded to certain groups in society. For instance, the society is privileged toward people that can walk, and until the law demanded it, people in wheelchairs did not have equal access). There was a time when a person in a wheelchair had to worry about whether they would be able to go to certain places. A person who is able to walk did not have to think about this. We're talking about the privilege involved here. There are many privileges that white people have not because they are racist, but because of social norms that are in part because of past racism.
Handedness privilege is not about whether right-handed people are actively oppressing left-handed people, it simply points out that due to the world being mostly right-handed, it is advantageous to be right-handed. This does not mean that left-handed people cannot succeed or adjust, but the adjustment is required to perform at the same level. When you use a credit card reader in a store, it conforms to right-handed people; for a left-handed person to use the card reader, they must either switch to their non-dominant hand or reorient their hand. "Of course it's made for right-handed people!" That's not the point, the point is that for a right-handed person, they are privileged because they were born into the dominant group, thus never have to consider or change how they do things because of their handedness.
Flesh colored band-aids are not racist, but when choosing to name the color, the makers did not consider skin tones that were darker as "flesh-colored." It ignores the fact that flesh has many tones to it, but standardized to a light skin tone. When you're using crayons as a child, darker skin students will realize flesh isn't meant to describe their flesh. It's not about whether intent was racist, but that a white person using such crayons will not experience such a scenario.
Flesh tone:
You may argue that it's not a big deal, but how many of these "not a big deal" things do you think people of color encounter? There is a cumulative effect here, no one thing impedes progress, but all together, it makes a difference. I've never met a black person that has complained about band-aids, but many of us know, "flesh means white." White people will never have that eperience. What about pale people? What about tan people? You can be ridiculous if you want, but the point about band-aids was to highlight something rather simple that favors white for no reason. Really, there shouldn't be a flesh color, that ascribes tone to a crayon or band-aid.