I should've phrased my comment better. I don't disagree with anything you mentioned. The post is correct. I just think they're overselling that aspect.
Leaving unused components in your workloads is indeed a security issue. A data breach takes over seven months to detect on average. During that time, the attacker is mainly squatting on your infra and finding deeper attack vectors to move laterally. This of course is a broad statement. Somethings are a lot harder to exploit than others.