In my view the only one to worry about (at this shock horror headline scale) is hemlock since it is so common especially in the weedy areas of childrens playgrounds and roadsides. However the unpleasant smell generally puts people off. Most of the other species listed are uncommon or are generally in habitats that are less visited. The giant hogweed can be a big issue too in some areas.
Of course all are indeed toxic so could cause serious issues but it is more about the scale and perhaps whether people should actually pay attention to the natural environment. Perhaps the shock horror should be that people have lost the ability to recognise these ‘dangerous’ species.
When I was young I was told a story about some children that had got a pen knife used it to cut the hollow stems of giant hog-weed into whistles.
They got very sore lips.
The population figure (28,000) for hemlock strikes me as being on the small side - I think it was Amadan who recently put up an observation of hundreds to thousands of indiividuals. Perhaps that was the number for giant hogweed.
Ha!
Maybe the Chicxulub event was just a brief (in geological terms) hiatus. They may be staging a comeback, with gulls and pigeons in the vanguard. Come to think of it, the visiting hen blackbird does have a gleam in her eye…
The NBN holds 28,104 records of Conium maculatum so I suspect that is where the figure comes from. It is a novel way of misconstruing biological records.