Facebook Third Party Authentication essentially a fail?

Most websites - that require authentication these days - lean on plugins from twitter or facebook.

It makes sense - especially on Mobile - why fill in a form - when you can login via facebook - with the Click of a button.

Ok so - what should authentication be concerned with:

• A safe and secure way of logging into a site!

So what has it become:

• You can login to our site - nice an easily - BUT if you take this easy path - we also want to data-mine your profile - for all you contacts - and all your posts.

Sort of sucks as an authentication method - sure you can login to our site - but we also want to spy on your completely non-related facebook profile/activity.