Right. The idea of NFTs is clearly fungible as the "link" to the actual content isn't protected against change, nor is the content protected against change or copying.

This is not what fungibility means. A coffee mug used by Guido van Rossum may be non-fungible with other brushes of the same make, merely because I value its provenance. Everyone unaware that I am willing to pay a premium will treat it as fungible. It is irrelevant how many other copies of the cup exist.

Similarly, you can create a thousand NFTs linking to the same content, but no one cares except misguided NFT skeptics, who somehow think this is an important fact.

If you want to exchange things of value, they must be immutable in and of themselves.

It is an important fact to realize the actual asset (immutable or not) is not directly tied to the tokens, especially if one is skeptical of this worthless technology.

This is of course non-sense, as OpenSea has been taking down collections aggressively for months now, including in some high-profile cases such as the Cryptophunks.