Snowden and Greenwald were always lying/obfuscating about their intentions and capabilities to “secure” the data that Snowden stole from the NSA.

Even the strongest encryption can be defeated with time and brute force. Countries like Russia and China have the resources to make that happen and they can direct all manner of tactics and techniques to do it. The NSA does it to foreign governments and their encrypted data, so why would anyone think that Russian or Chinese intel agencies wouldn’t try and succeed at doing it with a US cache of data.