Seems someone doesn't understand how OAuth works. It does not automatically give full access to your social media accounts, location history, and device cameras as the video says.
Using the Google button for instance will tell you exactly what permissions are being requested every time you login. Generally, it will be name, email, language, and sometimes profile picture. Aside from the profile picture you would give all the same information anyway to create an account. At least with OAuth there is no worry about passwords, especially for people who don't have good password practices and reuse passwords between different sites.