I think it depends, strictly ownership means owning the NFT token. By itself a token is just data.
Taking a step back the value of the token comes from Jack using the platform to mint it (which is purely off chain and you have to trust the platform verifies against the twitter apis correctly) and tweeting about it (again, off chain and you have to assume his twitter wasn't hacked).
Jack can delete his tweet but he can't delete a token that represents the tweet he sold. I can appreciate if you don't think this nuance matters but obviously there are some who think it does.
The same applies to physical goods. There's nothing stopping the original from being destroyed, your item being a near exact replica but if the interpretation that ownership of NFT is psysical ownership is accepted then you can't steal it and claim you are the owner without my private key.
Taking a step back the value of the token comes from Jack using the platform to mint it (which is purely off chain and you have to trust the platform verifies against the twitter apis correctly) and tweeting about it (again, off chain and you have to assume his twitter wasn't hacked).
Jack can delete his tweet but he can't delete a token that represents the tweet he sold. I can appreciate if you don't think this nuance matters but obviously there are some who think it does.
The same applies to physical goods. There's nothing stopping the original from being destroyed, your item being a near exact replica but if the interpretation that ownership of NFT is psysical ownership is accepted then you can't steal it and claim you are the owner without my private key.