The nature of the forum means that there's bit of churn and not every idea gets seen. There's no harm in trying to bring fresh eyes to an idea. I think it's kind of uncharitable to say "it didn't take".
It's not a bad idea, even the name "Mythbuster" isn't bad. It's not that the Knives of Artemis are myths, but that what do you call a rumor that's been verified untrue? It wouldn't be entirely inaccurate to say "Today we're testing the myth that there are only 100 Knives of Artemis"
So yes, as someone who very much enjoyed the show Mythbusters, I entirely agree with Chrono-bot that it'd be fun to have a badge named Mythbuster, and I'm sure that there are some people who would like that badge name for character reasons, and people who would like knives of artemis defeat badges for lore reasons.
I just think that the requirement to defeat more than 100 in one mission is important.