I don't think there ever really is a "final version" of any play or song. Every production of Shakespeare is liable to rewrite it, and it's pretty clear that Shakespeare did that too.

As I pretty clearly said, I wholly disagree with rioting against the play, or disruption of performances or threats to the people involved. But a belief in free speech includes a right to peaceful protest by people who felt it insulted them, for example leafletting playgoers.

As weelittledrummer said "The work we do does not exist in a vacuum and and it gains at least some of its validity from the audience." If the effect of the production has been to ensure that it won't be seen by Sikhs, that is a loss which I am sure would not have been in the author's mind. You can't challenge people to look critically at themselves if you have driven them away.