There is a lot of tracking Google does that couldn't just be instantly turned on at the request of a government if Google wasn't already doing it.
For example Google Analytics: if that product didn't exist the government couldn't just ask Google to install tracking scripts on half the websites in the world without anybody noticing.
You could argue that the government could force Google to create and market Google Analytics. But that just re-enforces the idea that we shouldn't be using Google Analytics - we don't even know if it isn't entirely a program created at the request of the US government (I don't actually believe this, but it's where you end up if you start worrying about the government forcing Google to change their business).
If you have a site where this would be a significant worry for you, then yes, you absolutely shouldn't be using a CDN (or, at least, should only be using it in limited ways; images are probably safe); the CDN provider or anyone who can control it can do you a lot of damage.
The correct analogy would be "by that argument, everyone should think very carefully about the pros and cons of using a CDN to serve part/all of their website".
Which.... is true anyway, regardless of the potential for government-enforced data collection.
For example Google Analytics: if that product didn't exist the government couldn't just ask Google to install tracking scripts on half the websites in the world without anybody noticing.
You could argue that the government could force Google to create and market Google Analytics. But that just re-enforces the idea that we shouldn't be using Google Analytics - we don't even know if it isn't entirely a program created at the request of the US government (I don't actually believe this, but it's where you end up if you start worrying about the government forcing Google to change their business).