Istagram is an American country, so it should probably be considered to be counter to the national interests of any country other than America and maybe America's close strategic allies. Particularly, if you're the leader of a country America considers to be a strategic rival, then you should definitely give serious consideration to blocking American social media.

Personally I think it's bad for America too, but it's unlikely that they're deliberately inflicting damage to America in an act of information/culture warfare. But other countries, particularly America's rivals, would be wise to assume that's what is happening to them.