You're not making sense to me. What is "This"?

You originally asked for examples of grand narratives. I didn't really provide a specific example, since if one believes in narratives of progress in one field of morality or ethicse, then he in general does believe in what I term moral progress. I dispute moral progress being a good hypothesis about how the world works, this means that I necessarily dispute anything objective-morality-ish being behind say a narrative on woman's liberation or the spread of Christianity or the end of slavery or the spread of democracy.

Considering I've run into such opinions several times, I think many still believe in moral progress. I criticized that hypothesis here (yes I really should finish the articles on this that I promised soon, but I wanted to read as much of old LW material as possible before that, especially the cited literature on metaethics).

So when I below said "This" I was talking about the above paragraph and the post I linked to.

This isn't a specific case of such a grand narrative but basically transforms any plausible moral narrative quite a bit.

Then I proceed to demonstrate how I think starting to take the idea of there being no such thing as moral progress seriously changes one's opinions on observation of moral change or even orderly and predictable moral change:

It becomes less

"We are on a path towards something like objective morality for humans. Yay the future is bright and I really should learn to accept changes to values of my society that I disagree with."

If you believe in moral progress than interestingly and quite anomalously our society claims that we have been seeing moral progress for the past 200 or 300 or X years. Basically the world is supposed to have at some period after humans evolved suddenly started to act as a sort of CEV-ish thing, the patchwork of human communities started to aggregate some improved and patched up morality or past preferences instead of just developing to fit whatever had the greatest memetic virulence or genetic fitness or economic value or whatever at that particular the time. Taking this as a given, one should then be pretty open to the idea that while the ethics of 2100 or 2200 might be scary or disturbing at first glance, they will be genuinely better not merely different.

"Something as uncaring as evolution may be determining future morality. Eeek! My complex values are being ground down!"

Most humans who really understand it don't feel comfortable with letting evolution continue to shape us, why should we hold lesser standards when it comes to a poorly understood processes that go into making people and entire societies change their values?