- Non-segwit transactions require 51% of the hashpower and a private key to steal. Segwit transactions just require 51% of the hashpower.
You statement is very confusing since you are taking about two things: a) 51% attack and b) stealing coins.
How can you steal coins without private keys on Bitcoin? What kind of bull shit is this?
Please enlighten me!
In big blocker world you dont need non mining nodes. Miners enforce and determine consensus. Therefore 51% attack can do anything they like including stealing coins without keys.