Surely that's at least in part just because of the contrast to the bloodshed and absolute savagery that followed when Yugoslavia splintered and the erstwhile Serb, Croat and Bosnian brothers started murdering each other?

No - it was an authoritarian regime but there was also a genuine belief in the Yugoslav project. It wouldn't have lasted as long as it did without that, it wasn't just sloganeering and coercion.

Didn't it all fall apart immediately when Tito died? That doesn't suggest a successful nation-building project that people believed in.