Earlier quoted context omitted.
People like to point at Japan and its lack of growth pointing out to various degrees how awful that is, but if you’re actually Japanese, you’re pretty much fine for these decades of zeroish growth. Not to say Japan is an idyllic place free from problems, but the economics of a zero growth society has at least that example of a distinct lack of doom. If the rest of us experience it like that, it’s not really anything…
"People" might, but the post you're replying to didn't. All they said was "Declining populations simply cannot maintain the “grow at all costs” current economic order" which implies a change is necessary, not whether that change is good/bad/whatever.
Meanwhile, the US has had any number of highly-adversarial, occasionally-violent political fights in the last decade while still in that "grow the top line" mindset.
You could make a plausible argument that those additional few decades of "growth" has a lot to do with the violence and unrest, even, not the other way around. (For instance, see any of a number of takes from all over the political spectrum blaming increasing stratification of elites.)
Hell, wasn't Marx predicting internal upheaval and self-defeat of capitalist economies many, many decades ago based on the same sort of demographics/populations/resources economic arguments? Things will change is an easy prediction, they haven't ever been stable. But it's also a meaningless one if you can't convincingly show that it's this decade not "any time between 10 and 200 years from now."