Having been part of the "XviD scene" for many years in the not too distant past, I have to say that the whole angle on this being profit-driven is just... wrong. NFO-files have been around since the early days of BBS trading in the Amiga scene and the PC scene alike, and the presence of web addresses in these files today doesn't change the reality that people just don't care for reading the NFOs when it comes to audi…
I have never seen anybody click on an ad on a webpage. By your reasoning that means that obviously no-one clicks them.
And yet google makes billions off it. Apparently 10% of internet users make up almost all the advert clicks.
I would agree that it's even more of a small % for nfo files and txt files in torrents because of the effort of getting to them. It could still easily translate to serious money when you're talking about 75% of the entire torrent ecosystem using only 100 peoples' torrents.
I have no facts, but the odd behaviour presented in this article makes me suspect you're actually way off mark as I find it hard to imagine that there is some small group of altruistic French seeders using one ISP who wish to bring the joy of movies and music to everyone for such a massive amount of effort.
The more likely explanation, just as presented in the article, is that there's good money to be made as long as you take the operation to scale.