This is talking about NFC file transfers. When it says “NFC is NOT secure”, it means the NFC transport provides no security. That doesn’t mean it’s impossible to use NFC for secure communications. Ethernet has no security features either (apart from requiring physical access, which doesn’t do much for you in a large building that’s open to the public and has ports everywhere), yet we do plenty of sensitive stuff over it, because we can add security at higher levels.
The key to preventing skimming attacks is, as others have said, that the transaction features a handshake of sorts which can’t be replayed, rather than just checking static data. NFC payment transactions do this, as do chip card payments.
