It's one thing to recognize your civilizational and societal achievements as good, useful and constructive and therefore love them and cherish them. Nothing wrong with positive self evaluation. Whoever sees a problem with that is an anti-intellectual.
However, for most people national pride is something that manifests as "we are better than them" and allows them to engage in all kinds of atrocities against other people because "they're outsiders/they're not us". It's very easy to justify all kinds of things when you adopt "us vs them" mentality.
Gotta be careful. Since most people can't be counted on to be well behaved and not let their pride devolve into justifications for colonization/genocide/ethnic violence, it's best to keep those feelings down to a minimum.
However, for most people national pride is something that manifests as "we are better than them" and allows them to engage in all kinds of atrocities against other people because "they're outsiders/they're not us". It's very easy to justify all kinds of things when you adopt "us vs them" mentality.
Gotta be careful. Since most people can't be counted on to be well behaved and not let their pride devolve into justifications for colonization/genocide/ethnic violence, it's best to keep those feelings down to a minimum.