Can someone define pay inequality for me? Is it that people with the same job ought to be paid the same? Having worked in the industry a while, I've seen many

Can someone define pay inequality for me? Is it that people with the same job ought to be paid the same? Having worked in the industry a while, I've seen many engineers with the same job, same title, and wildly different levels of productivity. Even people with less experience out performing those with more. I struggle to see how removing all nuance around actual ability within a band is a good thing, and suspect people armed with this information asking for raises are setting themselves up to hear they're just not that good. Human beings aren't fungible resources. While someone might be good enough for the job, it's unlikely they're exactly as good as their peers. I do think more information is a good thing, and as such making this available is great, but I don't think it leads to the outcome some seem to hope for.