When it comes to the personal and intangibles, then grow all you want; read the books, develop the skills, and so on. But when it comes to consumption of resources and economic growth then cancer is the right word as unbounded growth fundamentally results in unbounded growth of waste products and overconsumption of inputs.

There is no system or ecology that can support infinite growth; as long as we're stuck in the "coasting is dying" mentality we'll see productive entities develop dysfunctions as they outgrow their ecosystems or kill themselves trying to expand. If coasting leads to gradual decline then over expansion leads to catastrophic failure.

Not growing does not mean “coasting”.

There is a difference between keeping your car going 55 and letting your foot off the gas entirely.

In this case it’s being suggested that the former is better than continuously accelerating as long as possible.

That person must have never heard of Isaac Newton's First law of motion.