In my Intro to Philosophy class in high school, the first thing I learned was that "everything is relative." (Exception was made, of course,  for this statement, which, in itself, is absolute.) For every thesis, we can find an antithesis; and for every fact, there is a counter-fact. Nothing is absolutely bad nor  absolutely good. 

To consider a simple scenario, how many people, for example, would be happy today if they heard that death is dead. This may sound absurd, but it is certainly true. The death of death itself would make us happy because we all see death as a bad thing. In this case, the death that kills death would be our friend by the simple formula that "the enemy of our enemy is our friend." This is one of the rare cases where we would befriend death, since it would rid us all of a common enemy.

The same rationale holds true for any disease affecting the human race. If, for example, AIDS itself would fall sick today and hospitalized of an incurable disease, I assume that many of us would feel happy upon hearing that news. It's not like we like the disease that sickens AIDS in itself, but we appreciate the fact that it helps us delivering a fatal blow to a common enemy. Hence, the point I am trying to make here is that a bad thing can be viewed as a good thing and a good thing as a bad thing depending on the circumstances.

When, for example, I read about the collapse of communism, I saw it as a good thing. But when I read about how people died during the two World Wars, I saw it as a bad thing. When I read about the 1863 American Civil War, I saw it as a good thing. But when I read about Pearl Harbor, I saw it as a bad thing. Today, for example, when I hear about people protesting in the Middle East and Across North Africa demanding democracy and respect for the rule of law, I see it as a good thing. But when I read about how military officials are killing or beating protesters, I see it as a bad thing. I could take countless other examples to show how good and bad can alternate under various circumstances, but I guess that would not make my point any more clearer.

To conclude, what is happening in North Africa and, by extension, the Arab World, currently, can be compared to a contagious disease, one that is set to swipe away dictatorship and political corruption out of the entire region. In various other circumstances, we could see such a systematic political pitfalls as a bad thing: we would see it as a bad thing, for example, for people in France or Britain to invade the street tomorrow and ask President Nicholas Sarkozy or Queen Elizabeth to resign or give up the crown. But, in the case of corrupt dictators in the Middle East or North Africa, we can't help but to celebrate under the same situation.