It is said that Napoleon Bonaparte loved Chambertain, a wine from Burgundy, and he drank it watered down. Was Napoleon a brute, coarsely treating fine wine?
Au contraire. Burgundy wines at the time were not at all fine. They were so muddy and rough that  diluting them with water was the only way to make them drinkable. 
What about wine chilled with ice, like hard liquor on the rocks?  
Never! That’s the standard snob answer. 
A case in point. The 2007 Jaboulet Vacqueras you see in the above picture was so highly extracted, almost tarry, and so tight, despite its nine year old age, that it was nearly undrinkable. Not too different than Napoleon’s Chambertains, I presumed. 
A cube of ice, stirred in for a few seconds and then removed, made a world of difference. It softened the wine and gave it more nuance. It made the wine easier to drink.
The lesson: every wine convention has exceptions. You might be considered Neanderthal if you drink your fine wine on the rocks. But if you briefly mix an ice cube with the right kind of difficult wine and soften it down, this can make you look like an expert.  
Whatever it takes to make a wine drinkable is fair game.