In many cases, it's social virtue signalling, with no real sapience behind the actions.
See how virtuous I am empathizing with lower-order animals' suffering.
See how virtuous I am championing the sanctity of human life.
A lot of the latter can be mitigated: make those who want human life preserved "at all costs" pay cash-over-the-barrel into that "at all costs" effort, on an individual basis. Voluntary, elective euthanasia becomes an option when no one steps up to pay for the extraordinary efforts. They either withdraw their opinion immediately when they can no longer externalize their social virtue signalling choice's costs onto everyone else, or they go broke very soon and those who are suffering can make a free choice.
Or we can pursue the sane choice and legislate elective assisted euthanasia with safeguards like Switzerland's or other rationally-chosen parameters. It is long past time to recognize that our medical technology has far outstripped our ability to reliably deliver an acceptably high quality of life.