Using Scuds to target tanks or military bases is one thing. Using them to target rebels hiding in playgrounds at schools is something else.
New York Times, "Syria Uses Scud Missiles in New Effort to Push Back Rebels", quoting a senior U.S. defense official
So, using Scuds is not OK, but using children as human shields (what else would "rebels" do hiding in playgrounds at schools?!?) is OK? WTF!!
Note: The original quote in the NYT article has actually been censored, although it still appeared in the excerpt shown by Google:
The quote has also been reproduced by several other newspapers. See e.g. the story from the Boston Globe.