There are several reasons for keeping the parentage secret which have nothing to do with greed. (And if you know the Mansells, they hardly seem greedy to me).
1) If they reveal their TC parentage, people will start calling all crosses by this name which is just wrong. By keeping the parentage "secret", their seed grown stock retains more of its value, (as it should), and it prevents a lot of confusion in the market place. This has already happened anyway with many people referring to seed-grown thorelii x truncata as 'Red Dragon'.
2) There is much variation in seed grown hybrids and how anyone can look at a single example of a hybrid cross and since it is different from another example declare that the two are not the same cross is just ignorant. Personally, I appreciate the variation in the seed grown hybrids and grow several different forms of many individual crosses. Another good reason to differentiate between the TC lot and the seed grown ones. Since there will be many TC plants in culture, people will begin to know what to expect from them and the seed-grown plants will continue to be unique and hopefully provide pleasant surprises.
3) I also bought these TC clones as they are great examples of the crosses and may prove to be good parents on their own. I see no problem with having a "Black Dragon" as a parent instead of the actual species involved. In time, these crosses will attain their own cultural and characteristics knowledge base which will be more informative than knowing the parents.
4) By not releasing the parents, they are reinforcing their own names and pointing out the need to improve the registration rules and process.
5) Some people are hybrid snobs and by giving these varieties their own names, they reinforce their belief that these should be judged on their own merits and not how they compare to their parents. BTW, they are the creators of Predator and just look at how many people compare it to hamata. IME, I have focused too much on pitcher appearance and not enough on overall plant characteristics. Sure hamata has a nicer peristome, (and isn't that why we grow these), but Predator is an overall better plant from a cultural perspective, IMO.
6) I believe the parents are no real great secret and many people have been able to figure them out. If they really wanted to keep them secret they wouldn't have used the same pictures on their web site.
7) I find it kind of fun to play detective. Originally I thought Sabre was ventricosa x Trusmadiensis, but since that cross doesn't excell in hot conditions, I think they may have found that (maxima x thorelii) x TM is the better grower, and they do look similar. (Although the recent picture I've seen of (maxima x thorelii) x TM doesn't look anything like Sabre, hybrids do change a lot as the pitchers mature, (esp. with lowii in the mix), and since we are the first to grow these plants we get to experience the wonder of watching the pitchers change as they mature first hand. Another reason I love to grow hybrids! (plus they are usually much easier to grow).
End Rant.
BTW, I have no affilliation or inside knowledge of EP, so these are all just my own opinions.