this list is very extended and it does not mean that a chicken will die if it pecks some of those plants.
tobacco is toxic and we still smoke it, chew on it even sniff it (well i do) along with other toxic habbits.
i have fed my chickens potato peels and raw onion for months and they are still ok, i did this because i didnt know potato peels can go bad easily and become very poisonus if their exposed to the sun.
i also have a fenced vegetable garden and they have intruded it several times, but they never pecked the onions, the tomato plants or the peppers.
like you all have said i agree that if the chicken has no other options but a tomato plant, she will start eating it.
one of the reasons i left some weeds hanging around in the yard where they free range, i also found the toxic weeds and i patrol and remove them asap, they never seem to eat those tho.
dont go crazy with that list, it indicates what plants are toxic to chickens, it doesnt mean they are all fatal in any quantities, i believe the chickens know better