That principle doesn’t apply here, because you can use simple language to turn the words around, and then you have a positive, while the task of proving it remains the same.
Specifically: when you say you can’t prove that we don’t live in a simulation, then it is the same as saying you can’t prove that we do live in reality.
But “we do live in reality” is a positive. Now the words are different, but the task is the same: prove that we live in reality.
You can’t prove a negative.
The positive assertion is “we live in a simulation”. All that can be done is gather evidence to support this assertion.
That principle doesn’t apply here, because you can use simple language to turn the words around, and then you have a positive, while the task of proving it remains the same.
Specifically: when you say you can’t prove that we don’t live in a simulation, then it is the same as saying you can’t prove that we do live in reality.
But “we do live in reality” is a positive. Now the words are different, but the task is the same: prove that we live in reality.