There's something about left wing ideas that makes their holders assume they need no justification at all. Take this, from Chris Dillow:
I reckon it's luck, then, that explains almost all differences in income.But what of the case that luck should be pooled? Apparently, it doesn't need to be made. The case for intervention can be taken as read, the case for non-intervention needs justification, so long as it isn't too strenuous, because that would be ridiculous.
The question is: should luck be pooled or not? Right libertarians have good (if not compelling) reasons to say not. But if they claim much more than this, they are just inviting ridicule.
Begging the question is a basic logical fallacy, but it is amazingly common when this sort of view is expounded. I have never seen a reasoned and evidenced argument in favour of the principle of income redistribution. They always, somehow, either fail the reality test, as in the society is like a caravan idea (it isn't), or fail to make the argument, engaging in circular reasoning or claiming that a moral principle underlies the opinion of the writer.
In politics, claiming a moral foundation for one's views is exactly equal to saying that your opinion is just plain right, and cannot be discussed.
This lack of enquiry into their own opinions is the cause of many of the idiocies of the left.