Sounds like those people either don't understand what they're saying, or they're mindlessly shilling for Filecoin. Both are obviously shitty, but I don't think it's fair to point the team behind IPFS in a bad light because of what others say about it.
> I don't quite understand how come they claim IPFS is both a protocol AND a network of nodes AND not a storage
IPFS is a protocol, IPFS is also the name of the network. IPFS doesn't automatically distribute data, hence it's not "storage", but a protocol for doing storage.
In the analogy to TCP, TCP/http are the most common protocols, and the most common network is what we call "Internet". Initially, there was many competing networks, until eventually The Internet overtook all the other networks and essentially "won".
(edit: again, gross over-simplification about the history the internet and more, hopefully won't be too misleading. Better overview can be found here: https://en.wikipedia.org/wiki/History_of_the_Internet)
Reading your link I don't quite understand how come they claim IPFS is both a protocol AND a network of nodes AND not a storage. For example TCP is a protocol, but TCP is not a network of nodes even if there is a network of nodes using TCP to communicate.
I think this is some cheap wordplay to play pretend distributed filestorage and but also absolve themselves from any responsibility in case something goes wrong "IPFS is only a protocol, you probably was holding it wrong".