It appears he had a bad experience with them:

https://news.ycombinator.com/item?id=11833815

and is writing a book about it:

https://news.ycombinator.com/item?id=12749364

I didn't have a bad experience with them. I clean up their mess on the regular. It's a steady source of income for me — you know, people who rely solely on their payment processor to protect them from fraud.

They don't care to do any sort of diligence about who opens an account. Someone, like a fraudster, can use a demo template for Woocommerce, apply and be accepted, only to clean out other people's cards en masse and zero intent to operate as a legitimate business.