Facebook post by University of Helsinki

Choral singing is not just a hobby but also a platform for community building. It is perceived as healthy fun that brings different people together to take part in a creative activity. In Finland, singing is a popular activity even though attending and singing at church and political events has become less prevalent.
Singing creates communities but also demarcates them | University of Helsinki helsinki.fi

What is the communal nature of singing? What historical changes are related to singing?