Why is that?
That's easy. Liberals are more likely to have gone to public schools, to have learned using whole language, to have been told any drivel they wrote was "just fine," to never have learned basic logic, to have been socially promoted.......
Conservatives are more likely to have gone to private schools (at least grade and/or high schools), learned phonics, were corrected when wrong, learned and practiced logic, weren't promoted until they mastered the current year's material......
You catch my drift. I'll bet Hitchens went to a quite demanding set of schools.
Because all the truly intelligent writers eventually see through liberal leftist lies, spin and deception - and they become conservatives ala John Podheretz, and the guy who wrote the book, "How I became a member of the VRWC"!
The left's best writers stick to FICTION and -- if they must call themselves "journalists" -- clean up in the "Features" section of the newspapers.
Hitchens, plus Nat Hentoff and Michael Kelly. All are on the left, but they are not of the left.
The distinction that you are searching for is "respect for the truth". The good writers, whether from the right or the left, possess it. Intelligence and style begin with a respect for the truth. It allows them to discern right from wrong and limn the truth about each.
The leftist writers you rightly dismiss aren't writers at all; being propagandists and no longer able to even discern the truth, much less respect it.