The cache includes personal details that can identify users and could help adversaries create phishing attacks. The cache was exposed via a MongoDB instance that could be accessed without authentication. The data is currently uploaded to the HaveIBeenPwned service which allows users to check if their personal information has been exposed. It is legal to copy what is publicly available but it should not be used against the best interests of the owner, which is considered an offense by the owner of the data. Check if your details have been exposed on the web again.
Source: https://www.bleepingcomputer.com/news/security/unprotected-mongodb-exposes-scraped-profile-data-of-66-million/