This seems quite silly. As many other people have said in these comments, RST is an obscure mess. By contrast, Markdown is supported by every editor, every static site generator, countless other applications, and is trivial to learn and to use.

Also silly is to complain about stuff that everyone uses, like tables, not being part of the markdown spec. We have amazing tooling around markdown, like pandoc, who cares whether it's part of the spec?