Whataboutism is using the hypocracy of B to argue that A shouldn't be held to account for its misdeads.
Constructively pointing out hypocracy is to also call for B to be held to account. Whataboutism isn't constructive; it's obstructive.
In many cases, it's even worse. Whataboutism is often used to argue that the hypocracy of B negates the complaints of third party C against A. Nobody is claiming HP or the journalists have tried to hack the Chinese government, or that HP or the journalists support the NSA's misdeads.
Whataboutism impedes progress and should be called out when encoutered.
