This completely misses the point, and it's telling that it gets votes. The GDPR does not regulate what you personally know, it is about collections of information outside of your brain.
So if the same butcher took notes about his regulars’ preferences, they would need to be GDPR compliant?
What does US IP law have to do with this?
How are you about to answer that with US IP law?
> This Regulation applies to the processing of personal data wholly or partly by automated means and to the processing other than by automated means of personal data which form part of a filing system or are intended to form part of a filing system.
Which makes sense, just keeping customer data on paper instead of in digital storage shouldn't mean you don't have to protect it.
At this point it leaves your brain and becomes subject to the GDPR.