That figure seems to be derived from every group that has every used the ISIS/IS/ISIL/Daesh name and how many members it holds when all of those affiliations are added.
An excellent example is Ansar Bait-al-Maqdis from Egypt, often said to have merged with IS by the mainstream press, are still committing terror attacks under their own name. What seems to have happened as far as anybody can work out is that they announce a merger with IS but still continue to operate as their own independent terrorist cell, mainly because that proposed "merger" never actually happened because there's very little to merge with.
IS is presented in Britain as an organized military unit with cells all over the world and sleeper agents and the like. It's bollocks, they're a ragtag group of fascists who through the usage of symbology and the Western presses misunderstanding of how the Middle East was balanced made them into a bigger group than they ever were. It took our press up until about last year to stop confusing them with Al-Qaeda, a group that they have been specifically at war with for as long as they have existed as an organization.
We inflated their presence and now every group in the region wants to fly the black and white flag and tell people how "they're ISIS". But there doesn't seem to be any proper command structure, their "leadership" are constantly changing and dying - not just in terms of one guy to the next but they are literally moving across the world. There was a point a little back, maybe 6-12 months, where about four different people were proclaimed as leaders of IS ranging from groups in Sinai to groups in Anatolia and one bloke in Morocco.
If they had a standing army of 20,000 then this would be black and white. We'd invade, take out their standing army and leadership then be back in time for eggs and bacon sarnys. The problem is that nobody knows who IS are, including IS, because they're more of a brand name than an actual organization with a specific chain of command. That was always the strength of the Islamic terrorist factions since the 1960s, they understand that a fractured system of groups all having their own individual goals and co-opting the brand name is a better strategy than putting together an army to be crushed. The exact same thing happened with Al-Qadea after 9/11, it was apparently this big terrorist organization with its octupus legs everywhere. No nobody is talking about them and has barely heard a peep out of them for ages. Because they never existed in the way we are presented with it, people used the AL-Qaeda brand name as part of their own specific struggles and I have no doubt that if we thought about it we could go through the list of known groups in the Middle East and Northern Africa and find that there's a bunch of groups who were "part of Al Qaeda" which are now "part of IS" despite them having competing ideologies.
In ISIL-controlled territory, 8 million civilians living in ‘state of fear’ – UN expert
31 July 2015 – The Islamic State in Iraq and the Levant (ISIL) has engaged in widespread and systematic human rights violations of the most serious kinds in Syria and Iraq, brutally forcing some 8 million people to “assimilate, flee or face death,” according to a United Nations expert.
“These violations may amount to genocide, crimes against humanity, war crimes and widespread attacks on the civilian population,” according to Ben Emmerson, the UN Special Rapporteur on the promotion and protection of human rights and fundamental freedoms while countering terrorism.
An estimated 8 million people live under ISIL territory in Iraq and the Syrian Arab Republic.
“The brutal nature and overall scale of abuses appears to be intended to reinforce the group’s absolute monopoly on political and social life and to enforce compliance and conformity among communities under its control. The result is that civilians who remain in ISIL-controlled areas live in a state of constant and almost unimaginable fear,” said Emmerson in his report, which was presented to the Human Rights Council last month.
ISIL has targeted religious and ethnic groups in Iraq and Syria and committed acts of violence against civilians because of their affiliation with them. These communities have been forced to assimilate, flee or face death, he explained. “In Iraq, violence against the Yezidis have been reported with men being separated from women and children, then taken to ditches and brutally executed,” he added.
Extremely vulnerable to violence and discrimination, women face sexual and gender-based violence, including sexual slavery, killings, enslavement, and rape. They are confined to their homes and forced to adhere to a strict dress code, pointed out the expert. And children as young as six have been raped, tortured and kidnapped.
Children as young as 8 years old have also been trained and used in military roles. “They are reportedly made to watch videos of beheadings, and mass executions to desensitize them to forms of violence employed by ISIL.”
The growing military capacity of ISIL also means the spread of fear and terror on civilians, Mr. Emmerson continued, emphasizing that more than 20,000 foreign fighters have now joined the ranks of non-State armed groups from about 80 countries around the world.
Addressing the military response by the international coalition of States, led by the United States, he said that civilians living in ISIL-controlled territory are mainly residing in urban areas where many of the coalition air strikes have been performed. It has also been reported that ISIL strategically places its fighters among civilians, in civilian areas or uses hospitals and schools as military bases, to provoke civilian casualties in the event of attacks by the coalition.
The UN Rapporteur then called attention to the lack of transparency with coalition operations in Iraq and Syria.
“Each nation participating in the air war operates under unique rules of engagement, and transparency levels differ significantly,” the expert noted. While air strikes are carried out by different sources, it is difficult to know which States were responsible for an event and when they will occur.
The Special Rapporteur recalled the coalition states’ obligations under international law to ensure that their military operations are “transparent and accountable,” and that any civilian death resulting from these operations is “promptly, independently and impartiality” investigated.
Highlighting the failure by the Security Council to take appropriate and immediate action to protect civilians in affected areas, Mr. Emmerson also stressed the need for the international coalition of States engaged in military acts against ISIL to ensure that measures are put into place to protect civilians and prevent further casualties.