This should be called "Don't use Tailwind in a React library for a design system" as this really has nothing to do with Tailwind and is all about integration of Tailwind into a React design system.
None of these "negatives" are "negatives" for using it as part of a standard HTML/CSS website outside of React. The comparison between readability of a bunch of divs and web components or react makes no sense, of course <SidebarItem /> is easier to read then <div class="flex-1 bg-blue font-bold, text-md d:none"></div> but nobody writes React like that. Everyone will have a SidebarItem component that spits out that div.
None of these "negatives" are "negatives" for using it as part of a standard HTML/CSS website outside of React. The comparison between readability of a bunch of divs and web components or react makes no sense, of course <SidebarItem /> is easier to read then <div class="flex-1 bg-blue font-bold, text-md d:none"></div> but nobody writes React like that. Everyone will have a SidebarItem component that spits out that div.