People are definitely aware of the name. It would be a complete non-starter to have a name that didn't reference "markdown" in some way when the project is an effort to standardise markdown.
There are certainly a large number of people that are aware of the name, I'm not disputing that.
My point is that there are tens of millions of redditors that aren't. I would also guess most light users of Stack Exchange sites are not very aware of the name.
For all those people, I don't think the name matters. Also, the heavier, more interested users will likely not be disrupted much by a different name.
