I think you're right, I'm conflating two separate things.

EDIT: I am wrong (it's been a while) but there is nuance.

I said any computer program fails to prove some true statements. In fact, some 'true' statements cannot be proven by any program, as others have said.

But for those statements G, you can prove 'G is true if our system is consistent', just not 'G is true'.

So when we say G is 'true', we are really just asserting the consistency axiom that our computer program is denied.