There are bad singers and there are inexperienced singers.

The former should have the self awareness to know when it is appropriate for them to perform. Unfortunately some don't.

As I gained experience as a singer I realised how much practice it was taking to be simply mediocre. Then I discovered that not only was I a qood dancer but that dancing involved a lot more physical contact with attractive ladies than singing. These days I sing in the car and join in with choruses.