They're talking about all versions, not just 4e. All the nifty 3.5, 3.0, 2e, and earlier material that's now out-of-print is gone and no longer accessible. If you had a group still playing 2e, and a new guy joined who didn't know the rules, up until this boneheaded move by WotC he could still go to rpgnow.com and instantly buy the core rules, legally, and be able to read up on them. And WotC would get a large chunk of that sale as essentially free money, because it's the distributor that bears all the costs associated with hosting the file.
Now, the only legal recourse is to buy a used copy somewhere. And that doesn't profit WotC anyway.