A group of black-clad men and women armed with long knives slashed whomever they saw at a railway station in the southwest Chinese city of Kunming early this month, leaving 29 people dead and 143 others injured. The evidence found afterward included the flags of the East Turkestan Islamic Movement.

After Chinese authorities declared this was a terrorist attack planned and perpetrated by separatist forces from Xinjiang Uyghur Autonomous Region, some Western media outlets did not hesitate to put the blame on the Chinese government rather than the cruel terrorists.

When covering the Kunming carnage, the Associated Press interviewed Sean Roberts, a professor of anthropology at George Washington University.

The US professor is not unfamiliar to Chinese readers. He is the author of the notorious CNN article "Tiananmen crash: Terrorism or cry of desperation?" that triggered popular outrage in China last year.

In the interview, Roberts avoided using the word "terrorism" basically for three reasons: The violence was still "rudimentary in weaponry," it was unclear whether there was any "organized Uyghur militant group" and the attack did not appear linked to any "global terrorist network."

Judging from his comment on the Kunming attack, he seemed to be totally ignorant of basic requirements for defining terrorism.

Not surprisingly, his personal homepage reveals that he specializes in "nationalism, ethnicity, and development in Central Asia" and terrorism is not his area of expertise.

Although the international community has so far failed to agree on a uniformed academic or legal definition of terrorism, there is a minimum consensus in this regard.

According to Boaz Ganor, a prominent Israeli expert, "terrorism" is "the deliberate use of violence aimed against civilians in order to promote political goals."

The Kunming attack satisfied all the three requirements - "deliberate use of violence," "civilians" and "political goals" - for defining terrorism.

By US official standards, the Kunming carnage can also be designated as terrorism.

The US Department of State, for example, uses a legal definition of terrorism for its annual country reports on terrorism to the Congress.

The official definition contains four requirements: "Terrorism" is perpetrated by non-state actors, involves the premeditated use of violence, is committed against non-combatant targets, and has political aims.

In particular, the US definition does not require that the terrorism be carried out by a recognizable organization. The underlying cause is that the so-called lone wolves may even impose a greater threat than organized groups.

In accordance with the arguments of Roberts, the Boston Marathon bombings would not qualify as terrorism, because the two attackers were lone wolves, they were not connected to any global terrorist network, and their weapons were homemade pressure cooker bombs. However, Obama was quick to call the incident "an act of terrorism."

At a press briefing on March 3, the Department of State spokeswoman Jen Psaki had to acknowledge that the Kunming attack was an act of terrorism. But she still declined to characterize the Tiananmen jeep crash October as terrorism.

If the US had applied the same standards for defining terrorism in case of acts against its own people as against other people, it could have called the Tiananmen crash a terrorist attack.

In much the same vein, if Roberts had applied the international consensus on terrorism instead of his intuition at best or his prejudice at worst, he would also have had to call the Beijing incident terrorism.

The terrorist attacks in Beijing and Kunming are a mirror of Western hypocrisy. For many politicians, academics and journalists in the West, the word "terrorism" is only reserved for those they disapprove of, but not for those they sympathize with.

Such a double-standard approach is undermining the international cooperation on counter-terrorism.

Zhou Zunyou, head of the China section at Germany's Max Planck Institute for Foreign and International Criminal Law

Read more in Special Coverage: