People who keep animals that often die, should not keep them if they are not going to improve the environment in which they were keeping the animals that have died. Anemones may not have a brain or CNS, but they are not exactly stupid either. I find them pretty amazing actually.
Confusing or not, we took them out of their natural environment, so it is our responsibility to care for them. Rules are broken in this hobby every day, some actually become a learning experience with a positive result. We still do not know everything there is to know about anemones. However, we are a lot further than we were years ago. Lighting has been a proven factor.
On another note, every captive raised anemone that dies, could mean hundreds or even thousands of anemones that may never exist, increasing the chances that more will be removed from the ocean.