But I am confused about why people care if the account is open.
They had the account for years. It has some personal or sensitive data in it. Yahoo keeps getting haked. So delete the account and keep your data safe (by losing it forever). Except you can't keep the data out of the hands of the hackers. By design.
Do you have a better idea now of why someone would want an account on an insecure provider more secure?
They are relatively good but absolutely terrible. -- Alan Kay, commenting on Apollos