I don't think objectivity is an important feature of ethics. I'm not sure there's such a thing as a rationalist ethics. Being rational is about optimally achieving your goals. Choosing those goals is not something that rationality can help much with - the best it can do is try to identify where goals are not internally consistent.
I gave a rough exposition of what I see as a possible rationalist ethics in this comment but it's incomplete. If I ever develop a better explanation I might make a top level post.
Choosing those goals is not something that rationality can help much with - the best it can do is try to identify where goals are not internally consistent.
It often turns out that generating consistent decision rules can be harder than one might expect. Hence the plethora of "impossibility theorems" in social choice theory. (Many of these, like Arrow's arise when people try to rule out interpersonal utility comparisons, but there are a number that bite even when such comparisons are allowed, e.g. in population ethics.)
My girlfriend/SO's grandfather died last night, running on a treadmill when his heart gave out.
He wasn't signed up for cryonics, of course. She tried to convince him, and I tried myself a little the one time I met her grandparents.
"This didn't have to happen. Fucking religion."
That's what my girlfriend said.
I asked her if I could share that with you, and she said yes.
Just so that we're clear that all the wonderful emotional benefits of self-delusion come with a price, and the price isn't just to you.