IT saddens me greatly that I can’t write about sport in Scotland and just ignore the madness surrounding Sunday’s match at Ibrox. But to leave that aside and not mention what happened, and then ignore, too, the repeal of the Offensive Behaviour at Football and Threatening Communications Act of 2012 (OBFA) would be dereliction of duty.

I firmly believed back in my teens that The Great Divide between Catholic and Protestant in west central Scotland was only taken seriously by serious bigots on both sides, as was so superbly depicted by Peter McDougall, a man I have been privileged to know and write about, in the BBC Play for Today called Just Another Saturday, made in 1975.

Anyone who wants to know how bad sectarianism was in the 1970s in and around Glasgow should seek out a copy of Just Another Saturday and see how precisely McDougall portrays the ugliness of bigotry not to mention the horrendous violence that surrounded an Orange Walk back then.

I watched it again at the weekend, and was amazed at just how perceptive, and how violent, it was. Just Another Saturday would never get made nowadays, and some would argue that the lifestyles it portrayed are long gone.

Or are they? On Sunday we saw a sinister new development when a group of so-called Rangers supporters dressed themselves in black and marched to Ibrox, letting off flares and generally disgracing themselves and their club – the bit they don’t get - not least because of the flyer about Fenians that encouraged the march. The conduct of individuals within that group was utterly disgusting – the Goodnight Green and White banner, giving red hand, i.e. fascist salutes, and wearing black masks and balaclavas to hide their identities, as they knew fine well they would be committing criminality under OBFA.

The courage of their convictions did not extend to showing their faces. For them, football and Rangers were not the reason for their actions – they were the excuse.

At least those chanting Billy Boys and the Boys of the Old Brigade inside Ibrox weren’t faceless. In their thousands they sang, and there was an almost celebratory arrogant tone because they knew that with OBFA being repealed, they could revert to their ancient tribalistic ways.

For tribalism is the root cause of the bigotry and sectarianism that besmirches Scotland and Scottish football in particular, and though both clubs have often disavowed the sectarian elements in their support, there is no doubt that Celtic and Rangers are the tribal totems. That’s why the clubs have been latched onto by the tribe members.

Especially if you are young and easily pliable, you are seen to let down the tribe if you don’t join in the mass renditions of songs that if you sang them solo in the street would get you arrested because they are offensive – and don’t give me that historical culture nonsense because what does singing about being up to your knees in Fenian blood or praising the IRA of 100 years ago have to do with football?

That is the one question those who speak about freedom of speech can never answer – when one person’s freedom to sing an offensive song clashes with another person’s human right not to be offended, which has the greater priority? And I say it again, what has all this bigotry got to do with football?

It is all too easy to dismiss members of the two tribes and I do not do so for they sincerely believe in their tribe…and they are our fellow citizens, and probably work on weekdays beside people of different religions or none and get on fine.

But we can no longer dismiss what is going on as ‘Just Another Saturday’ and pass by, not when Scotland and Scottish football is harbouring what Alex Salmond has rightly defined as an ‘ism’ to rank alongside racism, homophobia and other hate crimes.

Sectarianism has to be met head on and defeated, and that means showing the two tribes the error of their ways, by law if necessary.

The problem with sectarianism is that to be in the tribe, you have to go along with the narrative that the other side are always the bad guys.

Then to be a leader in the tribe, you have to come up with ever more daring and damaging ways of showing your tribal loyalty, such as dressing up as neo-fascist ultras or letting off green flares in a stadium.

OBFA was an attempt to attack sectarianism in football – surely no one would deny that Scottish football has such a problem – but as I have written several times, it was flawed.

As a democrat, and an SNP member, I accept that it is going to be repealed. That doesn’t stop me thinking the repeal is a huge mistake as it clearly has sent out the wrong signal to some people who are perhaps not so much interested in political nuances and can now be tribalistic without fear of conviction – does anyone think Sunday’s developments weren’t connected to the repeal?

It would be better to await Lord Bracadale’s review of hate crime, but the other parties want to repeal the Act and that is democracy at work. So be it.

Of course all the trouble down the years could have been avoided if the Scottish Football Association enforced its rules which – as per FIFA’s overall laws – bar political and religious chants, song and displays in connection with football.

But the SFA taking on Rangers and Celtic, not to mention other clubs where sectarian, racist and other hate-filled behaviours are common?

Don’t make me laugh.