They didnt say that, they said there is no incentive for companies to give out data like that to the general public so they dont.
If it weren't so costly, I'd try to go to court with them, blaming them of fraud and tax evasion, that they don't declare all their sales and thus their income. And argue that because of this, it's a public interest to have access to the sales numbers, as it would make fraudulent actions more difficult if everybody had an eye on them.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/