It demonstrates quite the opposite. You can say 'i love my family and i accept that others don't'...so apply that to analogy to one of the moral situations we have been discussing...
"I disapprove of Tactdjff but accept that others don't"
"I disapprove of the Taliban burning people to death but i accept that the don't"
If you think either of those capture what we want to say morally about these situations you are deluding yourself to sustain your arguement...it's about as bad as analogy as you can get and well illustrates the inadequacies of the irrealist position here.
You'll have to explain you think I'm deluding myself , do you think the Taliban think burning people really think its wrong but do it anyway?
I’m quite sure the IS guy thinks his actions are ok – the problem with the statement “I disapproves of burning people alive but IS thinks its ok” isn’t that its false (as far as it goes) but rather that it doesn’t adequately express what we want to say about this situation morally. If morality was like loving your wife, and accepting that others don’t, then when people behave in ways we don’t like the best we can say is ‘I disapprove of that’. But in no society, at any point in human history has acts of moral condemnation ever just meant ‘I disapprove of you doing that’- when is meant by it is it is wrong, that the people doing it are worthy of blame...but we don't blame people for not agreeing with us about who to love or whether they should share our taste in marmite. We don't think they are wrong in having different tastes, it stops at the emotion/taste - they don't like it and that's that.
The same issue arises re my previous example of why we change our moral beliefs, including at times our core beliefs, we do so because we think our previous beliefs were mistaken and not because we have had a change of taste or emotion.
These aren't periphery elements of morality -they are absolutely central features of it.
There are other more technical problems too: If moral judgements were just emotional responses then how do we distinguish between moral and none moral domains of judgement? - Moral judgements have universally been treated as different from general preferences or ascetic judgements but there's no clear way to even demarcate these different sort of judgements if your analogy is correct. It gets worse still for your analogy, as expressions of personal preference derive their forcefulness from situational context but moral statements derive their force from articulation of rational arguments which presuppose impersonal standards.
There are also many cases in which find ourselves conflicted between what we want to do and what we feel we ought to do...in other words we pit rational standards of what is morally right against our emotions, tastes and desires. Further, as Syn pointed out on the last thread, if we analyse our use of moral language we find the use of the same semantic and pragmatic linguistic mechanisms to analyze their truth value as we do with factual claims.
I could go on the - whole assumption of fact-value division behind this view of morality is, as I discussed in an earlier post, woefully inadequate at describing our moral motivation and general cognitive processes - the way our conception of the world are simultaneously both descriptive and evaluative....
In other words comparing morality to loving your family is about as bad an analogy as you can get. When we create theories about morality their job is to explain morality...but treating morality as an emotion like loving your family fails repeatedly to explain morality as it is, and rather does exactly what I accused you of doing - trying to make morality fit your theory rather than the other way around. Your theory erodes our morality and just leaves us with a pale reflection of it.