“A critic enters the battlefield after the war and shoots the wounded”

American journalist Murray Kempton (1917-1997) is credited for writing that “a critic (or an editorial writer)  is one who walks down the hill, after the battle is over, and shoots the wounded.” That is, a critic (or an editorial writer) is unsparing.
 
Kempton first wrote the lines about Robert Kennedy (1925-1968) just a few months before his assassination:
 
“He (Bobby Kennedy—ed,) begins, then, under the heavy suspicion that he is the sort of man who suddenly appears on the field and shoots the wounded.”
 
The critic observation appeared in print by at least 1975:
 
“Murray Kempton is credited with this definition of a critic: ‘One who walks down the hill, after the battle is over, and shoots the wounded.’”
 
The editorial writer observation (probably directed at the New York Times) appeared in print by at least 1976:
 
“Columnist Murray Kempton once wrote that ‘Editorial writers are people who ride down out of the hills after the battle and shoot the wounded.’”
 
     
Wikipedia: Murray Kempton
James Murray Kempton (December 16, 1917 – May 5, 1997) was an influential American journalist and social and political commentator. He won a National Book Award in 1974 (category, “Contemporary Affairs”) for The Briar Patch: The People of the State of New York versus Lumumba Shakur, et al. Reprinted, 1997, with new subtitle The Trial of the Panther 21.) He won a Pulitzer Prize (category, “Commentary”) in 1985 “for witty and insightful reflection on public issues in 1984 and throughout a distinguished career.”
 
22 March 1968, The Spectator, “Bobby gets it wrong” by Murray Kempton, pg. 362, col. 2:
He (Bobby Kennedy—ed,) begins, then, under the heavy suspicion that he is the sort of man who suddenly appears on the field and shoots the wounded.
 
3 August 1975, Sunday World-Herald (Omaha, NE), “Critic vs. Reviewer,” pg. 2-A, col. 1:
Murray Kempton is credited with this definition of a critic:
 
“One who walks down the hill, after the battle is over, and shoots the wounded.”
   
7 September 1975, Washington (DC) Post, “...And ‘Wheat’: Wheat, Chaff and the TV Harvest” by Sander Vanocur, pg. H1, col. 3:
A critic has been defined as someone who comes down from the mountain after the battle and shoots the wounded.
 
Google Books
Investigative Reporting
By David Anderson and Peter Benjaminson
Bloomington, IN: Indiana University Press
1976
Pg. 173:
Columnist Murray Kempton once wrote that “Editorial writers are people who ride down out of the hills after the battle and shoot the wounded.”
 
29 June 1977, Washington (DC) Post, “In the Nature Of a Farewell ...” by Sander Vanocur, pg. C1, col. 1:
A critic has been defined as someone who comes down from the mountain after the battle and shoots the wounded.
 
With this column, I am coming down from the mountain.
   
Google Books
The Masthead
National Conference of Editorial Writers
Volumes 29-31
1977
Pg. 19:
It bears a quotation from Murray Kempton and reads: “All editorial writers do is come down from the hills after the battle and shoot the wounded.”
 
18 December 1979, New York (NY) Times, “Rich States, Poor States and Oil” (editorial), pg. A18, col. 1:
A critic was once defined as someone who comes down to the field after the battle and shoots the wounded.
   
2 May 1983, Chicago (IL) Tribune, “Tempo: Moving on, with a pause to look back” by Ron Alridge, sec. 2, pg. 12, col. 3:
I ONCE WAS introduced at a seminar by a man who wanted to explain exactly what a critic is. After some groping, and with a devilish grin on his face, he told thataudience that a critic is someone who watches a battle from miles away and then, when the fighting is over, walks over to the battlefield and shoots the wounded.
 
Google Books
California
Volume 10, Issues 9-12
1985
Pg. 71:
Somebody once said, “A critic is someone who comes onto the battlefield after the battle is over and shoots the wounded.”
 
Google Books
Politics of a Prison Riot:
The 1980 New Mexico Prison Riot, Its Causes and Aftermath
By Adolph Saenz
Corrales,, NM: Rhombus Publishing Company
1986
Pg. 172:
Newsman Sander Vanocher once described a critic as “one who visits a battlefield after the war and shoots the wounded.”
 
Google Books
Politics by Humans:
Research on American Leadership
By James David Barber
Durham, NC: Duke University Press
1988
Pg. 12:
... the old definition of the critic: the guy who comes down on the battlefield when the fight is over and shoots the wounded.
 
Google Books
Faint Praise:
The Plight of Book Reviewing in America
By Gail Pool
Columbia, MO: University of Missouri Press
Pg. 34:
A critic is someone who enters the battlefield after the war is over and shoots the wounded. —Murray Kempton
 
Google Books
Gore Vidal’s State of the Union: Nation Essays: 1958-2005
By Gore Vidal
New York, NY: The Nation Co, LP
2013
Pg. ?:
The late Murray Kempton once noted that although the New York Times likes to pose as being above the battle, this position has never stopped the Times, once the battle’s fought, from sneaking onto the field and shooting the wounded.