Yes, you are correct it is not only google but all the big tech. You are missing very important word here - based in US. My point is that those big companies were very reluctant to handle that data even if it was later proven unconstitutional.
For example service like Lavabit rather closed their operation than handing over your data. There were companies actually fighting this garbage instead of providing direct infrastructure for NSA to come and go when they need something.

But back to the original point that with google is your data very safe. That is not really true. Your data is a lot safer if you choose company which is an actual mail provider. With this you have an actual contract that will say they cannot handle your data for commercial purposes - you are the customer not a product and part of their side hustle. That puts google on the bottom of the list already. On top of that you can pick one based in EU and now you are protected even by GDPR and NSA cannot do whatever they want. Of course if you are a shady character you data will be handed over, but in a correct manner.