If only! The US has been obtaining intelligence information on private citizens globally without cause for decades, and this is well-known. It does this to Americans, Europeans, and pretty much everyone else.

When it makes sense to collect that data through its own signals intelligence, it does that. But Constitutional and diplomatic concerns often prevent it from taking such a direct approach. So it relies on private companies like Facebook or Google to harvest this information for them, and then relies on a variety of means to obtain it from there. One really obvious one is when it goes and buys that data -- for instance, while it would not be lawful for the police to directly track your location without a warrant, it is presently lawful for the government to buy location data from cellular providers in bulk, and it does so routinely. Similarly, it was happy to obtain information from phone companies to allow it to supervise the communications of pretty much everyone, without a warrant or individualized suspicion of any kind.

If companies like Google or Facebook don't want to sell the government what it wants, then it often simply compels them using the legal system, or quasi-legal processes that do not actually require judicial oversight, like national security letters that bypass anything resembling ordinary due process. This allows the government to greatly expand the already considerable reach of what is permitted under law, because even when these letters request data that the government has no right to, the strict non-disclosure provisions make it extremely difficult to fight. (For years, you weren't even allowed to disclose that you received an NSL to your attorney!)

And when it can't get what it wants by those means, it will use more aggressive tactics like secretly tapping communication links (as we know that they did to Google's fiber links between datacenters).

Encryption presents a threat to those methods. E2EE would mean that the government can neither purchase nor intercept the data, so at any given time there is always some effort underway to deter, sabotage or outright ban the adoption of meaningful encryption. This happens through legal means (by attempting to use the courts to compel manufacturers to break their own security, as the FBI attempted with Apple), quasi-legal means (such as laws like FOSTA/SESTA and attempted laws like EARN IT that don't directly outlaw privacy, but add so much liability that companies must undermine it themselves), technical means (as with the various key escrow proposals floated over the years), or outright lies and deceit (see: Dual_EC_DRBG).

The explicit, publicly-acknowledged motive in doing all of this is ensuring state security -- in the end, the same motive as the Stasi. Of course, the Stasi never had the sheer scale of information that the US Intelligence Community has access to. When GP says that the Stasi would be jealous of what the US has built here, that is clearly not hyperbole! Unsurprisingly, the EU is no longer thrilled to give unrestricted access to private spy agencies to operate against its citizens anymore. Again, none of that is hyperbole. It is actual, literal fact.

So, this is a "conspiracy theory" only insofar as gravity is a theory -- well-supported by a tall and unambiguous mountain of evidence, and is actually quite relevant as to why the EU does not want private spy agencies like Facebook compiling dossiers on their citizens anymore.