Thanks for responding.
Correct. Even Mengzi thinks so. He is claiming that we have the capacity to do good and we have the predisposition to do good. That isn’t the same as saying we’re innately good.
He thinks that the ‘external’ comes in helping us realizing and remembering that we have this disposition, which is too often and too easily forgotten.
Contrast this to Xunzi, who thinks we’re predisposed to be bad. Xunzi believes that the ‘external’ should focus on correcting and perfecting a corrupt human being.
A crude analogy would then be the difference between rehabilitation and punishment.
So Mengzi isn’t saying ‘let them be’, but ‘let them never forget that they’re capable of good’.
I don’t actually think either of them are right. Each person is different.