One of the things that sent me digging into this was people pointing out that starting with Celtic and Rangers is already starting too late.

Did anything in this surprise you, or is there another part of the Old Firm story you think deserves a deeper look?

Tour flaw is you're starting at a certain timeline, history goes back a lot longer than that.

M8 l have just found your channel  and l was so elated to listen to your message.
I have always been a believer in you're not born a bigot you're taught.
Now l come from a family mixed one parent Catholic, one parent protestant. When people find out l'm a Rangers fan, l'm labelled as someone who hates Catholics.
Growing up in Govan all my m8's were either Rangers or Celtic fans and we had no problem with it. My Mum would go to Xmas Mass every Christmas, but would always love to shout on us to go and see the bands/orange walk when they passed by our street, she liked it and always said when you grow up if you want to be blessed or baptised, then that's up to you.
And as l said l had many pals Catholic and celtic fans and we never had a problem. Since the birth of the Internet, it has only highlighted the divide, l didn't question why my pals went to a different school to me, because we were pals.
Even today in London as soon as l say l'm fae Glasgow and a Rangers fan, l'll labelled as someone who Hates Catholics, and trying to explain to my granddaughter, why her other grandad tells her l hate Catholics, because l support Rangers is tiring to say the least.
The look on their face when l tell them, l've been in Vatican and l've met Pope John Paul,
Such a joy 😂

What's the dartboard's role in all of this?

Good video and agree to a large degree.

However, you cannot do a piece on this without mentioning the discriminatory hiring policy of one of those football clubs and how it intentionally leaned into the edifice that was already there.

A good book to read is "how soccer explains the world"a whole chapter on Scotland

I think youve established concrete answers to the question of whether the clubs created the divide. The answer is no, it was already there. You touched on both clubs drawing and building off the back of that division, but you never detailed exactly why. How did that attachment become so strong with one or the other to enable another to build off the back of the opposite side of the divide? This is a question I have struggled to answer myself.

The British Empires methods is where this divide came from it's divide and conquer tactics

I don't know anyone who thought that football started the sectarian divide. Is this a joke?

One fact that amazed me was that Glaswegians and the greater Glasgow area are the only parts of Scotland that don't say "ken" , a study by Glasgow university attributed it to the mass influx of Irish souls in the 19th century, so it doesn't matter what foot you kick with in Glasgow, yous all don't say "ken" thanks to our Hibernian ex pats

They didn't start it, but they certainly help keep it going.

At the turn off the 18th/19th centuries, Glasgow famously had more anti-Catholic societies than there were Catholics living in the city. Anti-Catholicism long pre-dated Catholic immigration from Ireland.

Some other countries should follow our lead. Battles of politics and identity in the sporting arena (not that this is unique to Scotland either).

Imagine if US college football had our Sectarianism culture? It'd be a right stramash! And then there would be something worth getting excited about.

The Old Firm didn’t start the sectarian divide. But they have sustained it. And while there might have been grievances in the beginning that triggered some resentment. It’s a ridiculous rivalry now.

Whether the two clubs want to admit it or not, the reason Celtic and Rangers have become massive clubs is entirely because of religion, politics etc, this is the reason for the world wide fanbase ,if it wasn't for the sectarian nature of the clubs they would just be like a Partick Thistle or Clyde, the fact is they need each other to survive as big clubs, if you take one out of the picture the other without the rivalry would simply be like any other Scots club,, if they were to stick to their songs and chants within reason, and end any type of violent, ie, be like any other football rivalry then that would be fine with me, football is no reason for violence,

Do Catholics think that there is no history before the Reformation?
How do they think the Catholic church re acted to demands for freedom of worship?
Do they know what happened to the pre-Lutheran Protestants of Bohemia?
What happened to French Calvinists at the St Bartholomew Day massacre?
Why there are no, or very few, Protestants in Spain, Austria, or other catholic countries?
What happened to Scots Presbyterians under Episcopalian Charles II & Catholic James VII?
Why the 1680s are called "The Killing Time"?
Why Catholic schools in Scotland only have RC history teachers?
Why Catholics in Scotland demanded separate schooling when state funding was made available, something the catholic church was lax in supplying while responsible for this, while the Church of Scotland, responsible for the first universal education system in Europe, gave up their schools to non-denominational education?
Do they think that perhaps, just perhaps, maybe, the actions of their own church could possibly be a factor in how, especially the Reformed, other churches think of them?
And why do they think they can judge others but escape judgement themselves?

Maybe didn't start with the Old Firm, but the two clubs, some of their support and hundreds of social clubs linked to them certainly promote and encourage the religious bigotry in Scotland

All sounds quite convincing.
On the surface appears reasonably objective and balanced.  
However you miss a most important historical fact.
The Battle of the Boyne had huge consequences. Britain and large parts of Europe were for the foreseeable future saved from Catholic totalitarianism. A great sense of freedom arose In many countries. The Scottish Enlightenment  was in large part a result of the new freedom of thought. Edinburgh and Glasgow Universities blossomed and produced breakthrough new ideas and books.
According to Max Weber"s "The Protestant Ethic and the Spirit of Capitalism" , the loosening of the shackles of Catholicism worked wonders. He specifically mentioned  Scotland.
Present day Orangism is a mixed bag , to put it mildly . That does not alter the FACT  that 1690 is one of the most significant dates in European history. Still vastly important  because the question of religion is still at the base and centre of so many Political and Cultural disputes. The Vatican is still a major world player. Along with  its friends in the Mafia  Istanbul and  elsewhere.
What goes on between football supporters in Glasgow and West Scotland may seem small beer   but is part something very large .

The real hatred for the Irish was the iron masters and the coal masters used them as scab labor

The whole religion thing between Celtic and rangers was by and large manufactured