There is a lot of questionable stuff on ebay. quality- and legal-wise.
Occassionally it is handy; for example some people sell "used" ATP CD maintenance manuals. One might moan about the breach of copyright but these things are exceedingly useful to have.
Unfortunately, the line between somebody busting a price fixing cartel, someone busting a monopolistic practice, and someone selling a blatent ripoff with a copyright breach thrown in, is very thin.
I can think of more than one website which is putting out highly useful weather data which the UK Met Office contributes to under its treaty and other obligations but which the UKMO makes available only for a sizeable fee, and they would dearly love to shut down all these other channels which undermine their revenue. Same with P2P networks carrying current CAA charts that run on GPS receivers; quite an aid to flight safety if you ask me.
Aviation safety is nothing to do with making money, which is why the copyright holders don't like it.
Not referring to any person here in particular, but it's easy to get into a pot and kettle situation with this.