This is both true, and also useless: pretty much any E2E system is falling under this definition.
By definition you can't protect yourself from the entity that provides you the software you use, because you have now way to guarantee that they aren't going to backdoor you.
That doesn't mean it's snake oil though, as the entity you want protection against is generally not the software provider but a third party. Using e2e from a US-based entity means you are prone to spying from the US government, but at least you know you're reasonably secure against the IRGC, the Chinese intelligence service, the FSB, and so on.
It also means you are safe from data leaks, which are by far the most common threat today.
No system can be secure unconditionally, it's always secure under a particular threat model. And in practice “the attacker is able to deploy arbitrary code on your behalf for an extended period of time without being detected ” is a much narrower attack surface than “the attacker is able to obtain read-only access to your DB or your backups for at least a few minutes”. In the former case, the encryption being broken is also the least of your concern, as you've basically given remote access to all of your user's devices at this point…