Otherwise it's like dismissing NFTs and not minting your own but then getting upset someone did it on your behalf. You can't have it both ways.
Sure I can. I created the art, I own the copyright to it. If I choose not to sell prints of a piece, that doesn't give others the right to do so. Why would NFTs be any different?
And yes, somebody could copy my art and sell it on RedBubble. The difference is that nobody's claiming that a RedBubble shop is a definite proof of provenance. (But why not? "First RedBubble store" has the same level of credence as "first minted NFT," and it doesn't even require gas fees!)
Copyright is only valid in specific (sometimes geographically limited) legal frameworks and even then there are many nuances to take into account.
NFTs are just an easier way to establish ownership within the digital world, regardless of the chain (because of the timestamp I mentioned, since it can obviously be compared across chains).
> nobody's claiming that a RedBubble shop is a definite proof of provenance
RedBubble, being centralized, cannot be trusted to be a viable proof of provenance due to the possibility of corruption.
NFTs don't give anyone any right, they just make it easier to establish (and automate the process of verifying) ownership of a digital piece of content. They are not a replacement for copyright. Practically speaking you have two choices: you only claim copyright on some content, get mad when someone mints an NFT of it, try to identify and sue them (good luck with that) and waste time and money OR you mint an NFT as soon as you decide to publish your work.
There is absolutely no incentive in choosing the first option and if you do, well, that's on you.