This is not equivalent since it is reliant on the existence of the FSM, which is not usually taken to be proven, unlike (hopefully) the existence of other people.
How is the existence of other people proof of signalling theory? I believe you exist. Signalling theory could, for example, say I am holding up this argument on the internet because I want to show others how persistent I am. How does your existence prove or disprove why I am saying what I am saying?
A lot of behaviour that otherwise seems nonsensical can be explained by social signaling.
Why do rich people often spend tons of money on things they don't need or use? To impress other rich people.