http://en.wikipedia.org/wiki/Evil Evil is defined as something that is immoral, causes pain or harm, is offensive, or threatening.
The group of people I hang out with skew toward the definition I accept, but really it's just a definition. My real objection is that stoics (and many others) rationalize the current state of things as good. The alternative is to recognize that there are still a lot of big problems humanity needs to solve.
I consider the eradication of smallpox the second greatest accomplishment of humanity so far. The first is the green revolution, headed by Norman Borlaug. His new strains of crops saved about a billion lives in the 20th century.
With regards to earthquakes: Just because we can't solve a problem doesn't mean it's not a problem. I'm not offering a solution, just pointing out that earthquakes kill people. I don't want people to die, so that makes earthquakes bad in my book. It also makes disease, aging, and lots of other things bad. Is does not imply ought.