Because there's a difference between a license to distribute and a license to edit. If these guys openly bought to re-distribute (legal distribution license) then they were never considered the final owners, being as they weren't the final owners they had no legal right to edit because within the definitions of copyright law they never owned the movie, they merely held them waiting for someone else to pay them for it.
Also notice how many of the plantiffs rarely have their movies shown on broadcast TV or airplanes. Many directors put clauses in their contract not allowing external editors of their final product, so in order for the editing necessary for TV and airlines to happen they themselves would have to agree to do the editing or waive that clause. This would also put the editing companies in contract violation over and above copyright issues.
So, legally speaking, everything would be A-OK if the customer first bought a copy of the unedited movie, then stepped over into a different line in the same store to submit that copy to the editing department, to be picked up in a few hours? That way, the legal owner of the movie would be asking for the service.
If that's the case, what a screwed up system. The actions are all exactly the same, performed by the same actors, just shifted in time a bit.