It’s a markdown editor, but they can’t modify the markdown standard, so their scope is limited. All they can do is build features around it.
Having a database isn’t mutually exclusive with the core functionality. You can simply not use it.
Having a database isn’t mutually exclusive with the core functionality. You can simply not use it.
Everything more "advanced" like tables, to-do lists and multi-line code blocks aren't a part of the "standard" as it was written, but were added on top by different implementations (like CommonMark) which are now commonly-mistaken for the original Markdown.
My point being that this isn't something unique to Obsidian, pretty much everyone does it slightly differently while still calling it "Markdown".
They have several modifications of Markdown, everyone has. But not everything makes sense to implement in a flavour of Markdown. YAML is for structured data significant better than a freeform-format, especially when you're in the phase of building the foundation of a new feature-family.
The complain is valid, Markdown is for documents, free form, free flow, structured data are a very different use case, and while YAML is better for the job, it's still a different language with different smell.
But Obsidian is a tool for managing knowledge, always has been; it's not just a plain Markdown-editor. All those features which are going beyond simple flavoured text, have always been part of it's Core-Mission, just not materialized yet.