That's true. But the article is not titled "Why deadlines are pointless for creative processes." It's arguing that deadlines are pointless. Always. That's oversimplifying at best, click-baiting at worst.
I'd argue that even in a creative process, if you add enough of a safety margin on top of a conservative estimate, then a deadline can be expected to be met with reasonable confidence. This is absolutely necessary for doing business. "We release when it's ready" is a workable strategy when there are no obligations, but claiming that this always works in all other contexts is just not honestly considering other contexts.