Hi, Angelina Farmer, thanks for reading! The article does specifically state that the only way to cancel your membership is to cancel the recurring payment directly with PayPal. There’s a whole paragraph about it, but I appreciate you reinforcing the message. It’s an important one!
As far as anyone giving the IAPWE (or anyone else) their email and password, no one in the article, nor any of the posters in the comments did that. Nevertheless, I do think people who had memberships with the IAPWE should consider changing them in case they were somehow captured by their website. Better safe than sorry when you’re dealing with an unsavory organization.