[xzins]

So, you have taken the position that it is not possible to "always do the right thing."

Given your first answer, how do you answer the second question: "How does it hurt to imagine no one has achieved it?"

In other words, are there ANY ways that the knowledge or the fact of moral imperfection causes damage?

[Bloody Sam Roberts]

"In other words, are there ANY ways that the knowledge or the fact of moral imperfection causes damage? "

Well, yes I suppose there are.
One that pops to mind right off the bat is that some, seeing that others have tried and failed will assume that it IS impossible and simply give up and stop trying.
This can have consequences on still others whom would benefit from the efforts of those attempting to always 'do the right thing'.

Example: Joe Everyguy is reading the newspaper and says, "I see in the news that a guy got himself killed last night while trying to rescue a woman from a rapist. Semms the rapist had a gun and shot him. It just isn't worth getting involved so why even try?"

And BTW, I haven't necessarily taken the position that it is impossible to always do the right thing. I'm more than willing to give it a try. I'm just postulating some ideas that popped into my head, in a hypothetical vein.
Devil's Advocate type of thing, you know.