A load balancer is not much use if the application on the other side is borked because of the application code is faulty, I don't really see your point.
What I do see is 'devops' typically changing code in critical areas without taking sufficient care, but thats more a cultural thing than infra code being special.
Agreed and I'm from the "devops" side of the house.
I don't see a lot of build pipelines with automated tests and deployment for IaC. Standardized processes like pull requests with code review are also not ubiquitous.
With terraform one typically writes a template, does a plan, then apply and hopes for the best. What I've seen and the OP mentions the same in his talk is that things occasionally go terribly awry in ways that common software development practices would prevent.
If you make a minor mistake in application code, it usually doesn’t affect the whole site. Besides, when you are deploying code on a group of servers, hopefully you have sense enough to at least do a rolling deployment and are using automated health checks to make sure that your whole site isn’t down during a deployment.
What I do see is 'devops' typically changing code in critical areas without taking sufficient care, but thats more a cultural thing than infra code being special.