I get your point about PET bottles needing less energy to make and transport, but that is only looking at the energy use and co2 pollution.
You absolutely right there, but the article focuses on microplastics, another huge issue.
Is the microplastics issue worse than the co2 issue?
I am tempted to say “depends”, we don’t fully know the health impact of being exposed to microplastics constantly. We don’t know the long term effects of a planet being covered in microplastics, but it doesn’t look brilliant.
So you can’t say thay PET is outright better for the environment than glass.
PET is better in some ways, glass it better in others, which will win, no idea…