
Ive seen it done, and if its reallllllly necessary then i have no objections - for most dogs its not (those young, correct weight, healthy, correct coats, properly groomed, exercised sensibly not in the heat of the day..).
Its worth remembering though that if clipping softens the coat, for many dogs (especially those with a low wheelbase), this is one of the worst places to have a more easily matted coat.
If it needs to be done though and coping with the softer coat afterwards isnt a problem, then its the least harmful way of helping a dog cool down.
I do HATE to see shaven dogs, looking poo and too hot anyway, done through ignorance and idleness. (and only marginally less than i hate seeing horribly matted dogs who smell revolting.).