My daughter's age and younger have been taught in schools much more environmental impact, recycling, reducing concepts than I ever was. I can only assume that the little that I learned was more than my parents, and extrapolating that pattern to be true going further back in generations.
To that point, my dad would dump oil in the back yard, burn things in the barrel regardless of what they were, etc. (I grew up "in the country") Companies would openly dump waste into rivers (still happens, just not as openly perhaps because of the guilt/shame/criminality). The recycling of plastics was something just being taught as something to do when I was in school, but taught heavily for my daughter's age. Now, that's becoming a myth, so it'll be interesting to see how the teaching changes around plastics recycling.
The point is that some changes are not instant and are multi-generational concepts. The "talking about" is how that happens. To those that have already learned, it seems repetitive and ineffective. But that would be like telling an elementary teacher they are ineffective as they are always teaching the same things. The point is that it's new students each time. Those hearing the same thing they've already learned should just accept that they are not the target audience and move along rather than the negative commenting. Much like today's HN link on how transistors work. Um, like, duh, we learned that in school years ago. OR, maybe someone reading right now only learned software and is starting to get interested in hardware because of some project they want to try on an Arduino type of kit, but now really wants to know about the components.