A Google search didn't immediately clarify. What is 'SRE'? The most plausible de-abbreviation I could find was "site reliability engineer".
While data at Google is tightly protected, everything else at Google is fairly transparent. In particular, you can see who is using what resources. SREs, among other things, monitor and manage this resource usage. Large, abnormal usages ("Why is someone copying all this data off-site?") will be noticed, and some of the people who will notice won't take "because the NSA told us to" as an acceptable answer.
With many thousands of engineers it is totally possible for bad actors to have infiltrated Google. It's one of the reasons why there are such strict protocols for accessing customer data or production hardware. The idea is that by default no one has access to anything and that all accesses to data and production hardware are logged and audited.
I'm sure there're still opportunities for a rogue employee to do something bad but Google are way better at protecting access to their customer's data than many of the companies I've seen.
I can and do blame them without hesitation. They could choose not to store that data, or make it zero-knowledge-based, yet they choose not to.
Just because they've been compelled to hand over data via legal means does not excuse them for doing the wrong/insecure thing in the first place.
That's a pretty significant hedge.
Also, how effective are Google's processes against dishonest employees? It would not be hard for, say, the Chinese government to plant a mole in Google's security team. (Actually, the real nightmare scenario is a Chinese mole in Intel or Apple's hardware team.)