I cannot stand plastic grass, I see People using it every where with their new kids crawling all over it and admiring with pride their new pristine green coloured mats.
As you say OP the chemicals are one thing but that is just part of it.
As it degrades micro plastics leech into the soil, with toxic chemicals, this kills micro and macro invribrates in the soil, it infects and pollutes our ground water, it runs into our drains getting into both the food chain and water supplies.
It builds up over time and accumulates in all our species of wildlife destroying the eco system.
Replacing grasses and other plants and hedges with plastic increases traffic and other air pollution in our homes and surrounding areas which the flora once absorbed, causing breathing issues with their children.
Baby birds suffer when they hatch as parents can no longer forage as plentifully as they one did due to the lack of insects available. Baby birds are born with soft beaks, they need soft soil and lawns to get to grubs and worms. When replaced with plastic grass this habitat lost and the leached chemicals and heat from plastic lawns harden up surrounding soils.
Other species of mammals suffer, as they cannot dig fro grubs at night and when the do forage off plastic grass they consume micro plastic, plastic grass also holds no micro climate so there is no cooling and this also affects small mammals like hedgehogs and newts will dry up and die trying to cross it.
Sorry for the long rant but any one defending this stuff has zero consideration for wider ecological impacts.