This is a real, well-documented quote from British actor/writer Peter Ustinov (1921–2004). It appears on Wikiquote and multiple quote archives, with the full context usually being a longer passage criticizing Serbian actions and ideology during the Yugoslav Wars (especially the Bosnian War):

“It is unfortunate for all that no moral issue has ever been clearer. Any attempt to plea-bargain with outlaws and renegades will only be at the expense of honor, decency and self-respect. The Serbs are two-dimensional people with a craving for simplicity and an ideology so basic it can be understood without effort. They need enemies, not friends, to focus their two-dimensional ideas. Life for them is a simple tune, never an orchestration, or even a pleasant harmony. Animals make use of their resources with far greater felicity than these retorted creatures, whose subscription to the human race is well in arrears.”
— Peter Ustinov, The European (10 June 1993)

The version in the post is a slightly condensed/paraphrased excerpt but faithfully captures the original wording and intent. It was made during the height of the Bosnian War amid widespread Western criticism of Serbian forces’