The National Theatre's artistic director has said causing offence is part of the "business" of theatre.
Nicholas Hytner said theatre should tackle dangerous subjects
Audiences "do not have the right" not to be offended by works of fiction, Nicholas Hytner said in the wake of the closure of a play following protests by the Sikh community.
Birmingham Repertory Theatre said it was forced to cancel Behzti following violent demonstrations that threatened the safety of its staff.
But Mr Hytner said theatres and audiences did not endorse difficult subjects such as rape or murder just because they were in a play.
"The Western theatre was invented in Athens precisely to put on stage feelings that were too dangerous to experience in real life," he told BBC Radio 4's Today programme.
"Works of the imagination are designed to provoke powerful feelings. Through the theatre, those feelings are exorcised.
"The giving of offence, the causing of offence, is part of our business."
He added it was "desperately sad that we live now in a climate where the taking of offence is thought to be sufficient excuse for violence and intimidation".
Other leading arts figures have warned theatres may steer clear of plays that could be controversial.
Singer and artist Labi Siffre told the BBC News website: "A very sad day indeed. This step backwards in Birmingham echoes a global retreat on the journey towards spiritual, ethical and moral courage in reason."
Writers' Guild of Great Britain general secretary Bernie Corbett said venues may no longer "take the plunge" with risky material.
"If you can get a big enough crowd, then you can suppress something," he said. "That's an absolutely terrible principle on which to behave."
Mr Corbett said he was "very concerned" a play with artistic merit was scuppered by "a mob reaction".
"The whole theatrical community in this country is going to observe these issues," he said.
"Over the next months and years, it makes it less likely that they're going to take the plunge with anything slightly challenging or controversial, about any subject at all, where a mob might be whipped up.
"That's not necessarily a religious issue - it could be fox hunting or ID cards for that matter. Anything where you can get a mob in the street."
Things may get worse if a government bill to outlaw inciting religious hatred, which has raised concerns that it may make some religious performances illegal, becomes law, he said.
Mr Hytner also said the proposed bill should be looked at again following the demonstrations, saying the law appeared to "endorse the kind of violence and intimidation that we have seen in Birmingham".
"I do not know who is to judge what is a rant and what is the work of artistic merit, but I do not think the law has any business getting involved," he said.
Mr Corbett added: "We have to be strong and say even things that are offensive, and perhaps especially things that are offensive, need to have the protection of free speech and free expression."
Arts Council England also warned of a "blow to the emerging generation of artists from black and minority ethnic communities".
"It sends out a message that there are certain subjects about which they must never speak," chairman Sir Christopher Frayling said.
The arts had a role to generate debate and discussion about controversial issues, he said.
"It is a pity that this play has been prevented in this way from contributing to a considered debate."
But the council said it "fully understands" Birmingham Rep's decision, which was taken on safety grounds.
Jatinder Verma, artistic director of multicultural touring theatre company Tara Arts, said theatre owners may now think twice about putting on Asian material.
"This is a very sad day for the artists concerned, the theatre concerned as well as the community," he said. "No-one has come out of it well and it's a real pity.
"One of the implications, which I think is very, very serious, is the hesitation of other producers in producing work by Asians. I think that is clearly on the cards and that makes it even sadder."
He praised the Birmingham Rep for "making enormous advances" in producing work that represented its diverse community in recent years.
But he added: "Inevitably, it will now think very long and hard before commissioning other work."
And actors' union Equity called the decision a "matter of regret".
A spokesman said: "We take a line that artists should have the right to express themselves freely and that we don't agree with theatrical productions being closed as a result of this kind of pressure.
It had "considerable concerns" about the safety of the actors in Behzti as a result of the protests, it added.