I think hate of plastics is an emergent form of elitism.
Upwardly mobile middle/upper class people who've sort of "maxed out" the amount of personal identity they can buy with regular plastic things can unlock a new level of identity by deciding that plastics are bad for them and eliminating plastics from their life, a process which conveniently requires buying a whole new set of things that distinguish them from their peers.
This is the only way I can explain how irrational and inconsistent plastic-haters behavior is. There is so much invisible plastic in their life that they don't seem to care about.
Health in general has always worked like this, from supplements, to organic food, to avoiding ultra-processed foods, to gluten-free diets, pretty much every popular health fad has no provable causative effect on health.
Most of human behavior is irrational. If we were all perfectly rational, we would have healthy diet and exercise habits from the get go, and we'd have plenty of time to prepare food and exercise, because we wouldn't waste any time on entertainment.
You could just liken it to any pop health, dietary, or environmental fad instead of trying to portray a banal "people turn consumer choices into personal identity/lifestyle" trend as a whole new class of phenomenon. Crunchy hippies shop organic and audiophiles buy gold-plated premium wires; every subculture has at least a little bit of superstition.
Every plastic object replaced with a metal, or similarly strong/more solid material is an upgrade.
Even more so: plastics are not a specific chemical and they are not a specific material. Plastic is a category of materials that is very broad and very wide. You can make plastics out of almost anything. Therefore, to hate on plastics is to basically hate on an entire category of engineering and material design but not to actually know what a plastic is... sheer ignorance.
Are you sure it's all irrational? I, for one, prefer other materials for many things because they are more durable, hygenic or simply feels nicer. Seems perfectly rational to me. An irrational choice would be something like carrying a heavy canvas tent with wooden poles just because you hate plastic. Do you know anyone who does that?
> There is so much invisible plastic in their life that they don't seem to care about.
Huh? You think it's hypocritical for people not to "seem to care about" things that, by your own definition, they are ignorant of?
> requires buying a whole new set of things that distinguish them from their peers
No, it requires buying a whole new set of things to fit in with and be accepted by their peers, to distinguish themselves from the outgroup, the plastic users.
I don’t necessarily believe this is some emergent elitism; I see it more as a modern religion with many many rules about eating and consumption (using plastic is now a sin).
Like any religion, sinners (for example plastic users) are mostly pitied because they are ignorant, but those who know and choose to use plastic anyway, well, it’s OK to hate them.