Hugh

In 1900, the British introduced the first modern use of concentration camps.
First World War in Europe - 8 million military and 5 million civilian deaths.
The USSR/Russia killed 62 million people between 1917-1987.
Germany killed 21 million people between 1933-1945.
Some of the European Baltic States seem to indulge in tribal warfare/genocide (Serbia, Croatia, etc).

We need to be careful with the statement "these people", as European history seems to consist of a few of "these people".

Escapee, you need to read your history regarding "these countries" and "these people", as you stated above "These countries will never have peace, they will always be at war with each other". It was the United Nations/League of Nations, led by the US, UK, and France, that set up most of these countries, shoe-horning different tribes and ethnicities into artificial constructs to suit the UK/UK/France's political and economic requirements at the time.

Israel - Proposed, set up and initially administered by Great Britain in the 20th Century. Over three quarters of Israelis are European/American immigrants or their children or grand-children. Makes a bit of a mockery of your "these people" statement, doesn't it?
In 1917, the British Foreign Secretary Arthur J. Balfour issued the Balfour Declaration that "viewed with favour the establishment in Palestine of a national home for the Jewish people." In 1920, Palestine became a League of Nationsmandate administered by Britain. And of Israel's 7.1 million people, 76% were Jews, 20% Arabs, and 4% "others". Among Jews, 68% were Sabras (Israeli-born), mostly second or third-generation Israelis, and the rest are olim: 22% from Europe and the Americas, and 10% from Asia and Africa, including the Arab countries.

Iraq - Set up initially administered by Great Britain in the 20th Century.
During World War I, the British and French divided the Middle East in the Sykes-Picot Agreement. The Treaty of Sèvres which was ratified by Treaty of Lausanne led to the creation of the modern Middle East and Republic of Turkey. The League of Nations granted France mandates over the Syria and the Lebanon and granted the United Kingdom mandates over the Iraq and the Palestine (which was comprised of two autonomous regions: Palestine and Transjordan). Parts of the Ottoman Empire on the Arabian Peninsula became parts of what are today Saudi Arabia and Yemen. During the British mandate, the country was ruled by British colonial administrators who used the British armed forces to put down rebellions against the government. They selected the Hashemite king, Faisal, who had been forced out of Syria by the French, to be their client ruler.

Iran - The Shah was put in power by the UK/US, and his dictatorial behaviour led to the Iranian revolution in 1979.
In 1951, an eccentric pro-democratic nationalist, Dr. Mohammed Mossadegh rose to prominence in Iran and was elected Prime Minister. As Prime Minister, Mossadegh alarmed the West by his nationalization of Anglo-Iranian Oil Company (later British Petroleum, BP) that had controlled the country's oil reserves. In response, Britain immediately embargoed Iran. Soon after, members of the British Intelligence Service invited the United States to join them in covertly overthrowing the democratically-elected Mossadegh. Initially, United States President Harry S. Truman refused, but after Dwight D. Eisenhower was elected the British proposed the plan again. After convincing Eisenhower that Mossadegh was sympatheic to communism (even though he was an avowed anti-communist), the United States agreed to assist Britain in Operation Ajax. President Eisenhower authorized the CIA to take the lead in the operation of overthrowing Mossadegh and supporting a US/Israeli-friendly monarch. The operation was successful in triggering a coup, and within days, pro-Shah tanks stormed the capital and bombarded the Prime Minister's residence. Mossadegh surrendered, and was arrested on 19 August 1953. He was tried for treason, and sentenced to three years in prison. Mohammad Reza Pahlavi's rule became increasingly autocratic in the following years. With strong support from the US and UK, the Shah further modernized Iranian industry, but simultaneously crushed all forms of political opposition with his intelligence agency, SAVAK. 1979 saw an increase in protests against the Shah, culminating in the Iranian Revolution. The Shah fled the country again, after which Khomeini returned from exile on February 1, 1979 and eventually succeeded in taking power.

Lebanon - Set up and administered by the French in the 20th Century.
This area became a part of the French Mandate of Syria. On September 1, 1920, France formed the State of Greater Lebanon as one of several ethnic enclaves within Syria. Lebanon was a largely Christian (mainly Maronite) enclave but also included areas containing many Muslims and Druzes. On September 1, 1926, France formed the Lebanese Republic. The Republic was afterward a separate entity from Syria but still administered under the French Mandate for Syria. 40% of the Lebanese are Christian. Until the Lebanese Civil War (1975-1990), the country enjoyed relative calm and prosperity, driven by the tourism, agriculture, and banking sectors of the economy. It was considered the banking capital of the Arab world and was widely known as the "Switzerland of the Middle East" due to its financial power. Lebanon also attracted large numbers of tourists, to the point that the capital Beirut became widely referred to as the "Paris of the Middle East."

Pakistan - Less said about the fall-out from the British Empire in the Indian sub-continent, the better, I think.