There a phrase in show business that states, "The show must on." It means that regardless of what happens, short of the main attraction not being able to perfrom, the show that has been planned is still to be done for the waiting patrons who paid to see the show.
In this case, I don't think the promoters said that, but decided out of fans rioting for the show to go on. They're claim it was fear that led them to continue.
Green Day is being criticized for performing, but this is what they were paid to do. They were fulfilling their contract.
The performer knew the risks going in, so this was his own decision to take this kind of risk. People who went knew this could have happened.
The public knowledge that the performer was gay came out after the show. I'm not sure if it changes anything.
The Show Must Go On
Empty spaces what are we living for
Abandoned places I guess we know the score
On and on, does anybody know what we are looking for
Another hero, another mindless crime
Behind the curtain, in the pantomime
Hold the line, does anybody want to take it anymore
The show must go on
The show must go on
Yeah
Inside my heart is breaking
My make-up may be flaking
But my smile still stays on
Whatever happens, I'll leave it all to chance
Another heartache, another failed romance
On and on, does anybody know what we are living for?
I guess I'm learning (I'm learning), I must be warmer now
I'll soon be turning (turning, turning, turning), round the corner now
Outside the dawn is breaking
But inside in the dark I'm aching to be free
The show must go on
The show must go on (yeah yeah)
Ooh, inside my heart is breaking
My make-up may be flaking
But my smile still stays on
Songwriters
BRIAN MAY, FREDDIE MERCURY, JOHN DEACON, ROGER TAYLOR
Queen - The Show Must Go On Lyrics | MetroLyrics