

Are you talking about the client app, or about the service?
Much of what you said doesn’t apply to the service, which stores hashed phone numbers and first access / last access times and nothing else.
And the client does store these things, but also lets users delete messages and contacts. Your message deletions can propagate as well.
You literally don’t understand how hashing works, got it. Please educate yourself on this topic. In short, “connecting your existing contacts” is ENTIRELY possible with hashed phone numbers; it’s not even complicated or tricky. To claim otherwise, as you just did, is nothing but trumpeting your own ignorance.
As for deleting (and propagating deletion of) messages, this is most definitely NOT a matter of “just trust us”. The client is open-source! We KNOW how it works. We KNOW that deletion propagates across devices when you tell it to. We KNOW that the service cannot see your unencrypted messages, and that the encrypted messages are made with AES so even quantum computers in the future can’t decrypt them. This is incredibly far from “just trust us”.