How did you not know this? Makes me think you missed a lot more behind the scenes.
What else would you expect? The amount of flack people get they post a Show HN is getting out of control.
GDPR is not a new or surprising thing, and the absolute basics should be known by any developers working with private data. It's frankly shocking if they didn't know while starting a company in the UK, and I don't know if it's worse if they didn't know or didn't care.
This is a business that it will be vital that they are following regulations, and if they're skipping this, why should I trust they're following the rest?