Does google simply have access to you analytics data to do whatever they want? I was under the impression that they could only use it in ways that you the account holder defines.
It depends on what you mean by "access to your analytics data." Anonymized, aggregated data is being used to inform product decisions, but engineers don't have direct access to the production database to query whatever they want. There are almost no cases where you'll be granted approval to look at real user data, and if you are granted access, 100% of your activity is monitored.
As a side note, this has been the case at every big company I've worked at, not just Google.
