You can very safely remove the “probably” from your first sentence.

Agreed. Don’t make a threat - just make the GDPR complaint. Inform the company if you want. How many times have you remembered to follow up on one of those threats to see if you should still make a complaint?

It’s not infantilization. These bills are designed to prevent “one more hoop” design by the company to make it too annoying to unsubscribe. Your position assumes good faith behaviour by the company with the newsletter. That is absolutely not a given.

They’ve simply run the numbers and decided it would cost more to support the blind man’s access than they could get from plundering the blind man.