They're bootlegs... Why do you think they're being released now in Region 1 on DVD? Because they haven't been released yet...
I agree that those DVDs are bootlegs but there are a good number of titles that are legally available in other regions around the world on DVD that haven't been released yet.
DVDTalk.com has a forum devoted to International DVDs and there is a thread that keeps track of titles available exclusively outside of America.