I'm aware. Markdown is more popular and (in my opinion) easier to use. Tapping two spaces before each line of my code is a lot more effort than typing 3 backticks before and after the whole snippet. You're asking me to track indentation, on a potentially already indentation-based language (I mostly paste Python), without the help of an IDE. No thanks.
Sure, they could have figured it out. But it's annoying.