But can't the same be said for rationality and science? As Descartes showed a "demon" could continuously trick us with a fake reality, or we could be in the matrix for all we know. For rationality to work we have to assume that empiricism holds true. Why couldn't the same be true for ethics? I think that if science can have its empiricism axiom, ethics can have its suffering axiom.
The problem is that ethics can work with other axioms. Someone might be a deontologist, and define ethics around bad actions e.g. "murder is bad", not because the suffering of the victim and their bereaved loved ones is bad but because murder is bad. Such a set of axioms results in a different ethical system than one rooted in consequentialist axioms such as "suffering is bad", but by what measure can you say that the one system is better than the other? The difference is hardly the same as between attempting rationality with empiricism vs without.
A couple of years back I stumbled across this diagram on reddit. Since then I've kept a list of all illogical arguments, quackery, irrational ideas and similar nonsense, to pass the time. The count as of today stands at 1229 irrational ideas (a few could be debated perhaps). Hopefully you'll have a laugh or two! Any additions let me know!
Link to the list:
https://docs.google.com/spreadsheets/d/1T3HQ6TnCg6Q44WzpJPFxLvfqbfvKmT5RqvpGI3ji1y8/edit?usp=sharing
And the original diagram: