Sad day for Atomic Wallet users, It's (another) stark reminder. Not your keys, not your coins.
Atomic wallet is a non-custodial wallet and gives you the private keys. The problem with Atomic wallet is that it's close source and there is no way to know how the keys have been generated and whether the user is the only who has access to the keys or not. 
I got ate up for closed source on 1splitkey, even though it was split keys people didn't trust it.
I now know that lack of understanding means lack of trust.
I closed source code as it was tesla agents that controlled systems and didn't want that repurposed via simple cli tweaks. That was my reasoning. What's theirs? Why where they so successful?
These occurrences prove that they arnt always non-custodial.