The distinction of terrorism refers to the organized and intentional targeting of civilians, to induce terror in a population. Why can't we stick to being clear about that? Just because a certain group employs this strategy more often than most, does not mean all murders by people of that group get labelled terrorism.
That's a grotesque simplification of the motivation the term is meant to describe. I understand concerns about racism and generalizations, but that doesn't mean we should stop even trying to be factual about why people do the terrible things they do. When someone kills people because they lose their temper over loud music, road rage, racial hatred, or parking spaces, they're not a terrorist, no matter what color their skin. That's not what terrorism means, no matter who does it.
When an organization attacks innocent people, simply because they make a convenient target with which to make an ideological statement, it's an extreme attempt to terrorize society into listening. It doesn't matter what that ideology is. Whether it's religious, atheistic, or political, that's when it's terrorism. No matter who does it.
As such, most of us condemn terrorism, no matter who does it. The intentional murder of innocent civilians is unacceptable, no matter what the ideology behind it. Whether it's Buddhists in Burma, Americans protesting police violence, the Israeli military, or Islamic fundamentalists. It isn't about condemning those within our own culture, so much as condemning an abhorrent tactic, in any culture.
The condemnation such acts call for, being directly proportional to the amount of support they have. It's become controversial to make a distinction between a lone crazy person, and an act representative of a larger group, but this also matters. Nobody supports the lone crazy person. From Adam Lanza, to Jeffrey Dahmer, to Craig Stephen Hicks, you'd be pretty hard pressed to find anyone saying such acts are justified. As such, condemnation almost goes without saying.
Terrorism, on the other hand? As hard as it may be to believe, there are quite a lot of people who argue that it's a legitimate tactic. That intentionally killing people who are just minding their own business isn't substantially different from engaging enemy combatants, or that it's an understandable act of desperation, or even entire organizations predicated on waging literal jihad. The fact that this is widely disagreed upon is the reason it calls for overt condemnation. If we are not clear on this, then we are decidedly ambiguous about something that unfortunately does not at all go without saying.
Yet, by blurring the very definition of terrorism out of existence, we might as well be condoning it. By suggesting that it's the same as any other brutality, we suggest that it isn't any worse. When we don't discern the difference, we draw a moral equivalency that does, to an extent, implicitly support terrorism. It becomes just another form of violence, but no worse than recklessness, rage, or even self-defense. Terrible, of course, but one helluva big step closer to being excusable.
Essentially, that's the point of moral equivalency, isn't it?