> protects the confidentiality

For their definition of "confidential", which they can change at any time.

> certain limited circumstances

If they only intended the "required by law" example, they wouldn't use such a broad - and completely undefined - set of circumstances.

> guard against external threats

Google may have good security practices now, but an continually growing collection of highly-revealing tracking data is a very tempting target for many businesses, governments, etc. If Google (or anybody else) wants to claim that they are protecting your data, they should indemnify the subjects of their spying against any damages those caused by those "external threats".