People
There is perhaps, no more dangerous man in the world than the man with the sensibilities of an artist but without creative talent. With luck such men make wonderful theatrical impresarios and interior decorators, or else they become mass murderers or critics.
— Barry Humphries

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker claims that refined taste without the ability to create is a hazardous combination. Harmless outcomes include managing stage productions or arranging rooms; worse ones are violence or harsh criticism. The joke lumps critics in with mass murderers, mocking thwarted aesthetes with dark, deliberately exaggerated humour.
Context reviewed