I understand a utility of a specialized and featured editor. However, in case of Markdown, it seems that it was meant to be handled in whatever editor user edit

I understand a utility of a specialized and featured editor. However, in case of Markdown, it seems that it was meant to be handled in whatever editor user edits/reads text files. This way it can be both written and read anywhere. It's just structured text. If anything, a Markdown "viewer" or HTML-preview is what was usually a requested/expected feature. So that the simplicity of Markdown could be leveraged for authoring web-pages. But this could be done with a browser plugin, as well. Many text editors these days have some ways of visually highlighting Markdown elements in the text, just as any other syntax highlighting. In my experience, another editor just for Markdown is an overhead. LaTeX/MathJax could be written in more dedicated editors, as it's really not Markdown, and as much as it's convenient to keep everything in the same text file, complex formulas are not easy to visualize in text without rendering. And if indeed such a mixed "Markdown" file needs rendering, then it's rather a source file which asks for some Makefile to automate the assembly and rendering, rather than asking for another full-blown editor with its internal rules and options.