Such an advice coming from surveillance authorities, perhaps it's a Harvest now decrypt later strategy?
Harvest now, decrypt later, also known as store now, decrypt later or retrospective decryption, is a surveillance strategy that relies on the acquisition and long-term storage of currently unreadable encrypted data awaiting possible breakthroughs in decryption technology that would render it readable in the future - a hypothetical date referred to as Y2Q (a reference to Y2K) or Q-Day.
The most common concern is the prospect of developments in quantum computing which would allow current strong encryption algorithms to be broken at some time in the future, making it possible to decrypt any stored material that had been encrypted using those algorithms. However, the improvement in decryption technology need not be due to a quantum-cryptographic advance; any other form of attack capable of enabling decryption would be sufficient.
The more data, the better for surveillance authorities in the future, when E2EE is somehow broken.
Maybe I'm too paranoid, but this (Harvest now decrypt later) is an ongoing known strategy.