The existence of Islam is due to Muhammad making it the supreme Tribe of Arabia.
It is, by default, a tribal culture.
The Arabs of Arabia were a raiding culture. An Arab accepting Islam became part of the Muslim tribe and could no longer raid his own people. They went forth and conquered.
As is pointed out, not so much different from the rest of the world.
Except - Islam never did form nation states as did Europe, separating religion and State.
However, the Muslim empires were no different from any other empires throughout history. Some good; some bad; some stable; some unstable...
With the dominance of Europeans in the 19th Century and the complete disintegration of the last Ottoman Empire - Islam changed.
As always, it started in Arabia. The tribe of al Saud, after two previous attempts at conquest over the previous 175 years, finally conquered and consolidated the Arabian peninsula under their new death cult version of Sunni Islam, the Wahhabi cult.
The Saud/Wahhabists were the true proponents of the non-Islamic philosophy - convert or die. However, they applied this philosophy to the otherSunni Muslims of the Arabian peninsula.
The Shia, largely due to European and American protection, were able to somewhat escape the slaughter and dominance of the Saudis in consolidating the now absolutist monarchy of the tribal "kings" of Arabia.
However, these conquests began the present Great Sectarian Civil War of the Arab world, which has affected and spilled over into all of Islam, as the Saudis have exported their death cult Wahhabist philosophy to the entire planet until it has replaced normative Sunni Islam today. All of the radical, terrorist, Islamist Sunni groups today, descend from Wahhabism.
With the modern free for all in the Arab world, other Arab "chieftains" arose, wielding the swords of European exploitation and military prowess. Nasser; Saddam; the Assad's; the Shah; Quaddafy; and others.
Both the religious fanatics and the secular fanatics were based on the same tribal ethics - the demagogic leadership of the chieftain and merciless Arab raiding tactics against their enemies.
Shia Islam attained it's own death cult with the invention of Khomeini's Vilayat al Fiqh, "Rule of the Jurist," that conquered Iran and began exporting its own terrorist philosophies throughout the world.
Islam and Arabs are locked into a death spiral with themselves. The rest of the world; "Dar al Harb;" the "Far Enemy," is incidental to the savage battle that Islam and Arabs are fighting against the "Near Enemy" in their supposed "Dar al-Islam."
Attacks against non-Muslims; non- Arabs - the "West;" Israel; America; whomever, are merely coup points and street cred for any particular faction or sect to gain more adherents and demonstrate their power over other Arab or Muslim factions and sects.
The Muslim and Arab world is not barbaric because they are murdering non-Muslims and non-Arabs - that is all just "politics."
The Muslim and Arab world is barbaric because they ripping each other's throats out - slaughtering each other in ever increasing mountains of blood.
And, yes, their spillover into the rest of the world could well destroy portions of planet Earth and massacre billions of those non Muslims and non Arabs who are merely content to watch them annihilate each other in ever increasing brutality.
As did the European secularists affect the entire planet as they ripped out each other's throats (and anyone else they could lay hands on) during WWII while those merely content to watch tried to avoid getting involved....
Remember - if the Germans and Russians (and Japanese and Chinese) and all of the rest of the players in the game of world domination would have had nuclear weapons and other yet untried weapons of mass destruction during WWII, they would have used them - as they used poison gas in WWI; as the US used the atom bomb as soon as they could...
When you add a suicide death cult philosophy to weapons of mass destruction, you create something resembling the end of the world....