Tell me why you would you ever want to send an output to yourself that costs more in sats to create than it is worth. Any good wallet would prevent you from taking this unnecessary loss.
No. Good wallets give you the freedom to do as you like. There are infinite ways for the user to mess things up if they choose to do so, the wallet cannot prevent you from every. For example, paying unnecessarily high fees is (and should be) allowed.
Samourai acts as a surveillance app, sending everyone's financial history to their servers.
I have not used that samourai software, but don't they warn you that if you do not run your own node you rely on someone else's? What else should they say?