Seriously, and even if tex isn't perfectly secure, who cares? I don't think people compiling foreign latex documents is a big prize for any hacker, there's just so many more easily weaponized attacks.
Which is ultimately frustrating if you ever try to go back to an old document, and realize you don't have the exact markup engine that you used back then, so that you can't actually rerender it.
Now, to be fair, often this is ok. In particular, you might not care about how it rendered before, and a minimal markdown is fine.
However, if you do care about presentation, it is maddening.