Yup. Going to the third party provider as if it owns your data is a complete bypass of the 4th amendment. To make an analogy it would be like the federal government having to serve a warrant/court order/gar order only to your local mayor to search your house without your permission.
Imagine how messed up that would be. Yet, it's exactly what happens in the digital world, and somehow we've learned to take it for granted. If it's your data, the warrant should be served to you. As for terms of service and such of online services that say once you upload your data to their cloud, then it becomes "theirs", that's complete bull, and such a thing should be made illegal.
It just occurred to me, they figured out how to serve a complaint against your property (civil forfeiture) so I'm actually half surprised they don't serve warrants against the house not the house's occupants. Or even better, just serve the data itself; US Government versus 134,612 bytes of Data!
"So essentially the government has carte blanche to get whatever they want"
I think your quote answered your own question.