I'd love to say it was isolated, but my wife worked for a big 4 consultancy firm straight out of university. Just do a Google search for "Ernst and young happy day". I'd paste a link, but I'm afraid I'd actually have to watch it again...
https://www.ibm.com/ibm/history/exhibits/music/music_EO1.htm...
I only bring it up as there are just so many parallels in American culture that would see corporate team building and identity type activities as a natural extension: prep rallies, cheer leaders, pledges, marching bands, frats, school songs, etc.
These activities have some parallels outside the US, but they're activities that can seem distinctly 'weird' and not done to the same extent if you come from outside the US.
And not only do we have actual history (ibm) and many contemporary US companies doing these kinds of practices, in many ways the practices make much more sense if taken as a natural extension of already common American cultural practices...
It's no coincidence that corporate anthems like this sound similar to the Scientology hymn We Stand Tall: https://youtu.be/XyNh1j3dsp8
š For we're about to toast š
š The corporation known in every land... š
Starting workday with everyone standing in attention outside and singing company song when company flag was hoisted did not go well.