This article is pre-espresso, pre-percalator, and pre-vac pot even.

I would get a lot of stomach aches, grogginess and coffee burn out from drinking regular drip. Though he is describing some sort of weird tea-like method for drinking coffee, I imagine it's as bad.

Drinking a few espressos does not give me any issues, unless there is an issue with the extraction and I can feel like I've been poisoned. You have to trust your barista.