Based on some of the feedback here we’ve gone back to our lawyers and worked with them on an updated version of paragraph 6 of the new Terms of Service that should describe our original intentions better. The new version explicitly states that we can only use this data to enable you to use the Plex service. We have similar language in our current Terms of Service and this was unintentionally removed in the version that was published yesterday.
This page has been updated with the new version: https://www.plex.tv/about/privacy-legal/terms-of-service-may-2018/