uhm generally it's skill/show off issue..
also it's not always country vs country.. people in country A can still disklike other people in country A, the
analogy doesn't hold up anyway because viruses don't care for borders..
the argument that antivirus companies make them to keep up profits doesn't work either, since you have some free to
use anti-virus scanners, or even completely free, like 'clamav' is.. and these scanners aren't any
worse..
I'd see 2 reasons for creating a virus:
1. showing off your skills (personally don't find this a good one)
2. showing vulnrabilities in systems, like one can do with hacking (there must be betters ways, but ey, people are
stubburn)
3. as a political action, where you aim the virus on something you disagree with (I really wish there was no need for
political actions, yet there is.. if this is a good one? no idea)