Even then it sounds bizarre, was the public really alerted to his existence as a result of the release of a few obscure documents?

I thinks so, it was a story of a national hero who was hunted by his government for being different. The great injustice is type of a story that spreads really well (and sells). Movies came out, so I think people had higher chance to learn about him.

Wasn't all of that already known though, or is my sense of time quite badly distorted?

The movie certainly helped, I would put that as the biggest reason the general public heard of him more.