Once you understand the concepts it's not hard to debug. It's fair to acknowledge that kubernetes is complex, but also we should not ignore the real work that has been done in the past few years to make this stuff more accessible to the developers that want to learn it.
Also, saying it's not "alone" in this example I think is not fair. What would you count as "alone"? Setting up the kubernetes cluster from scratch and writing your own helm charts? Using that same logic, I can't say that because someone else designed and built the hardware it's running on. I think it's fair to say that if someone, independent of coaching, regardless of the underlying infrastructure produced some production grade infrastructure by themselves, they certainly did it alone.
As for debugging. You do have a point that it becomes more difficult. But, this also holds true for any of the alternatives discussed her (lambdas, terraform). I'd argue that when it all comes down to it, that because you can spin up the entire infrastructure locally on things like minikube, that it makes it many times more easy to debug than other cloud-provider-only solutions.
Should everyone go back to assembly on bare metal, then?
I think you mean silicon though.
But that's the thing though: they didn't do it alone. You literally pointed out that this wasn't true almost immediately: "leverage the helm chart open source community". They used the work of others to get to the result.
Also, I highly doubt they could debug something if it went wrong.
I simply cannot believe anyone would advocate, or believe, that because a Helm chart makes it simple to create a complex piece of infrastructure it must also be true that maintaining it is also simple. It's really.