Well, perhaps because in each case there were Islamic fundamentalists who wanted to see the more secular government toppled so they could install a more Islamic government?
You think Egypt has a secular government???????????????????? Tell that one to the Copts. The dictator Mubarak has been on a jihad against indigenous Eastern Christianity since the day he hooked up with Nasser and we've made sure he could get away with it. As I said before, the Copts I know are excited about this uprising and have confidence in the future. If they thought an Egyptian Khomeini was on the way, they wouldn't feel that way.