These questions have exercised minds again after Lennon was alleged to have been verbally abused and spat upon at Tynecastle last weekend. Not for a first time the Celtic manager was the subject of some embarrassing newspaper headlines.
It would be tedious to cite the entire canon of Lennon abuse episodes of the past dozen years in Scotland - it clearly suffices to say he is a targeted figure. There have been court prosecutions and prison sentences doled out to some who have chosen to make attacking Lennon their chosen sport.
What is going on? What is it all about? Why is Scotland repeatedly embarrassed by this activity?
For me, there is no one exclusive cause of the abuse of Lennon. Indeed, I would cite three distinct roots of this behaviour.
First, Lennon is sometimes abused for being a Catholic. Second, he is sometimes abused for his Irish ethnicity. Third, some of the abuse of Lennon is linked to neither religion nor Ireland, but to his personality, which many appear to detest.
The first of these - anti-Catholicism - can scarcely be disputed. Parts of Scotland continue to haul themselves slowly and painfully out of the 19th century, but until that process is complete - if it ever is - then public figures like Neil Lennon will continue to bear the brunt.
Scotland's anti-Catholicism is also inflamed in the football environment, wherein Celtic and Rangers remain mired in a regrettable context. This scene is changing, mercifully, and progress is being made. But the brute lump of sectarianism which remains ensures that a figure like Lennon is a magnet for bigots.
Anti-Irish prejudice? This is a more complicated theme, but it certainly exists in Scotland. I don't overstate it - this country is not saturated with anti-Irish prejudice, which would be an absurd claim - but strands of it for me are clearly visible.
It is an oddity that, in north America, ethnic roots appear to be encouraged and celebrated, such as the Irish-Americans in Boston, or the Scots-Canadians in Nova Scotia. Yet here in Scotland, strangely, the Irish-Scots are somehow deplored, disparaged or denigrated.
President Theodore Roosevelt once implored of his countrymen: "Stop being hyphenated Americans…please just be Americans."
But this was in a tender age of wartime, especially during the First World War, when German-Americans found their feelings compromised by the conflict.
In more recent decades, Roosevelt's words have come to look outdated. Today people's ethnic origins are openly valued, all across the globe, especially in the so-called "migrant age". So why the Irish-Scots come in for their abuse seems out of kilter.
For some, Lennon represents just such a figure. Moreover, his political view of "the Irish question" might not be to everyone's liking in Scotland. Whatever the case, the Celtic manager attracts those who need to vent their spleen in this context.
Yet one problem here is, some people want to make anti-Catholicism or anti-Irish prejudice the be-all and end-all of the Neil Lennon saga. But they aren't. They cannot be. There is too much evidence to dispute such a claim.
On Saturday night, when news of Lennon's assault at Tynecastle came through, I was in a BBC studio and being invaded by people who - some of them hundreds of miles from the Tynecastle scene - were decreeing the incident to be "sectarian" or "anti-Irish" in nature.
I always find this a strange scenario. Those who (rightly) despise anti-Irish prejudice often seem to crave every single episode to be just such an instance.
Last Saturday night, I was being told, there was no argument about it. Pure and simply, Lennon's experience at Tynecastle was said to be a faith or ethnic attack. People were emphatic about it.
Well, Lennon himself came out later and disputed this. Indeed, he put quite a tin-lid on the purveyors of zealous anti-Irish hurt by claiming that his verbal assailants at Tynecastle were simply footballing piss-heads who had had far too much to drink.
Some of those who cannot breathe without seeing anti-Irish sentiment in Scotland had their head in their hands at Lennon's words. I mean…how could he possibly say these words?
The truth is, on top of the blatant prejudice Lennon has faced, many others in Scottish football simply deplore him for his character, his personality.
Lennon is feisty. He stands his ground. He can provoke - he says so himself - when he wants to. To many, he comes over as strutting, or arrogant, or conceited, or whatever.
For this, some choose to hate Neil Lennon. And on occasion, such as at Tynecastle, that hatred produces a pretty ugly scene.
I don't mind adding a personal note here. I like Lennon a lot. In so many respects I find his public image totally at odds with the private man.
This is a guy who can be the most placid, withdrawn man in a pub, but who out of nowhere will suddenly be the subject of aggression. It is quite extraordinary.
Lennon is many things. Very often, a victim. On occasion, no innocent. Certainly, no shrinking violet. And he continues to hold up a mirror in the face of Scotland, upon which a pretty embarrassing truth is revealed.