I agree with the sentiment on your breakdown, but it's important to recognize the distinction between the technical definition of politics, and the colloquial one: most people mean partisan, mainstream, and/or heated discussion of government policy that's highly controversial. If you stretch that colloquial definition just a tiny bit, once any discussion gets contentious, groups start to form, and they start adopting talking points that fall on deaf ears to the other side, that's when you could get the average person to consider it a "political" subject.

The person you responded to pretty clearly was operating under the popular meaning of the term. I've given people similar spiels to your own, but there's a thing people mean when they refer to something as political or apolitical, and while there's theory and textbook definitions to draw upon, there's also value in getting to the crux what they're trying to say even if they don't use important words in the same you do. There should probably be a succinct disambiguation, is it lowercase p politics as in the workplace latter of office politics, or is it the uppercase P Politics where the discussion is over society-level legislation and policies? Ubiquitous politics vs niche politics? Perhaps there's a book someone wrote on the subject 50 years ago that we can use as gospel on the correct way to refer to these different concepts.

There's a certain level of (near) unanimous group cohesion that doesn't feel political to participate in because everyone present seems to be in agreement to keep the peace. Without a political "other" being formed for each side to mock and deride, disagreements are relegated to personal taste matters that people can just agree to disagree and still allow each other in the same space. I think the key is when people start strategizing how to get more people "on their side", because one of the goals of political action is to rally other people onto a cause. The dynamic is markedly different, with a shared group purpose with the future at stake.

There are times when a subject is worth bringing issues to light to spark politics within a "non political" group. To give an example, I'm really glad that the ethics of designer dog breeding has been called into question and heavily criticized, because some really fucked up things have been done to the genomes and resulting quality of life of countless dogs. I'm sure there were plenty of people who bemoaned the Animal Rights Activists coming in and "bringing politics" into the prestigious activity of seeing whose dog with a genetically squashed-in nose could run the farthest despite its impaired respiratory system. In situations of that vein, where harm is being actively done and bringing attention inspires positive change, the naysayers can cry harder and deal with it. I'm not a vegan but I can get behind the cause especially on a policy level to end meat subsidies and even outright ban factory farms.

But there are plenty of situations where a big-P Political topic doesn't need to be brought up, especially if it's almost entirely tangential (and especially if it goes beyond one or two relevant threads under an innocuous post). If there's an ethical problem, a bad actor, or some other injustice, by all means: speak up. Otherwise, it's best to respect people just having a chat over a hobby or admiring art; not every comment section needs to be railroaded into the same tired talking points about how everything is degraded under capitalism and the climate is being destroyed (points I'd almost certainly agree with you on, by the way). They have their place and they shouldn't be pushed aside entirely, but that place isn't anywhere and everywhere.

There is value in having spaces where people do not have to be reminded of stressful things; we have enough of those already. The mental health benefits alone to not having 24/7 doom spiral content can't be overstated.

At the same time I do think people need to just be okay with ignoring, hiding, or manually filtering out content they don't want to see, because at the end of the day it will pop up in unexpected places from time to time. There are plenty of ways to do that on Lemmy, I know Sync has some pretty good filtering features for those who want them. I would encourage people to make use of said filters as needed, even if just to improve the overall experience and reduce spam that would show up in their feed.