I guess the pride comes from having the same blood of those who make those achievements. Or culture. Or. Maybe it's because there's still trivial mind and you need to make a boundary between your group or collective (eg nation) to another so you can feel superior and unique. Happen with other things too.
I like my country but I am proud more of my family achievements. From peasants/mine worker to mid class safety. Whatever I like about my country is not even things like Peruvians in these decades did but prehispanic cultures and the Spanish things, food nature and animals.