When I try to sign up to Dropbox via Google, it says it requires me to consent for Dropbox o access and DELETE my contacts. Why? Can I override this?
Google Contacts uses the People API, which has two modes, read only and regular mode.
In regular mode, the application can modify contacts, including deletion. Dropbox may want to add Dropbox user account info into your contacts or something like that - it's not explicitly asking to delete your contacts for you, it juts wants to be able to modify them.
You aren't able to decline this permission and continue signing up for Dropbox with your Google account.