If they can't link Bitcoin money to a bank account, why they are closing some accounts. They connected those two somehow.

https://www.reddit.com/r/Bitcoin/comments/7ojg07/chase_bank_closed_my_business_account_of_over_10/
https://thebitcoin.pub/t/banks-closing-accounts-because-people-bought-btc/11434/16
https://www.cryptostache.com/2017/11/21/bank-america-froze-bank-account-buying-crypto/