If Bin Laden and the Saudis had such irreconcilable goals, why is there a whole line of thought blaming Saudi Arabia for his brand of religious extremism, and indeed, for enabling or resourcing him?
Because their idealogies doesn't fit in with rational thought. Most far-right ideologies aren't flexible for realpolitik, running a nation or doing anything done except engaging in war and even then, that has a lot of variation.
If Bin Laden and the Saudis had such irreconcilable goals, why is there a whole line of thought blaming Saudi Arabia for his brand of religious extremism, and indeed, for enabling or resourcing him?
You seem to be under the impression that he considered the USA to be his main enemy.
He actually considered other Muslims (the wrong types of Muslim, governments that he disagreed with, Muslims with different r religious interpretations, etc) to be his main enemy.
You also wrongly assume that other Muslims and Muslim government's would gladly cooperate with him if given the chance.
It requires Osama to cooperate with the Saudi Royal Family, who he hated for their basically secular lifestyle and for a bunch of other reasons.
Because there are a lot of ignorant people out there?
Bin Laden was an anti-western extremist even in the 1980s (foreign correspondents knew to be wary of him because he took out hits on foreign journalists).
A lot of not-dumb, and not-uninformed, people have attributed some responsibility for his movement to the Saudi's state-sponsored religion.
Many intelligent board members attribute modern jihadist movements to Wahhabism (or Salafism) and attribute that movement to the Saudi state. I think this all requires more unpacking than your pithy little retort implies.
Who did he take out hits on?
Western journalist John Miller was able to meet with him without personal harm.
What secular lifestyle?
This is ruling family that banned certain forms of worship in the 20th century, who had the cultural self-assertiveness to impose restrictions on the worship and gender roles of foreign soldiers who it invited to protect them, and some whose members have killed their own daughters for violating cultural taboos.
https://en.wikipedia.org/wiki/Death_of_a_Princess
http://www.iiwds.com/said_aburish/a_schunberg.htm
I always heard that the first thing that angered Bin Laden about the Saudi royal family is that they invited in US troops for their defense in 1990, instead of accepting his offer to protect the country with mujhadin, not any particular domestic policy or misconduct. So it sounded like he reduced his religious value system down to a geopolitical scorecard from the beginning.
Who did he take out hits on?
Western journalist John Miller was able to meet with him without personal harm.
Various books and multiple news reports have charged that the C.I.A. armed and trained the Afghan Arabs, and even bin Laden himself, as part of its operation to support the Afghan rebels fighting the Soviets. While the charges may make good copy, they don’t make good history. The truth is more complicated, and tinged with varying shades of gray. The United States wanted “deniability” that the C.I.A. was funding the Afghan war, so its support was funneled through Pakistan’s Inter Services Intelligence agency (I.S.I.). In turn, the I.S.I. made the decisions about which Afghan factions to arm and train, tending to favor those that were the most Islamist and pro-Pakistan. The Afghan Arabs generally fought alongside those factions, which is how the charges arose that they were creatures of the C.I.A.
Actually, the Afghan Arabs demonstrated a pathological dislike of Westerners. Peter Jouvenal says, “I always kept away from Arabs [in Afghanistan]. They were very hostile.” BBC reporter John Simpson had a close call with bin Laden himself outside Jalalabad in 1989. Traveling with a group of Afghan mujahideen, Simpson and his television crew bumped into an Arab man beautifully dressed in spotless white robes who began shouting at Simpson’s escorts to kill the infidels and offered a truck driver $500 to do it. Simpson’s Afghan escorts turned down the request, as did the driver. Only when bin Laden became a public figure a decade later did Simpson realize that he had been the mysterious Arab who wanted him dead.
In short, the C.I.A. had very limited dealings with the Afghans, let alone the Afghan Arabs. And since the Afghan Arabs functioned independently and had their own sources of funding, the C.I.A. did not need them and they did not need the C.I.A.
Afghanistan was bordered at that time by countries whose regimes were hardly sympathetic to American interests: Khomeini’s Iran, the U.S.S.R., and China. The only possible conduit to the rebels was through Pakistan. American assistance to the Afghans began in 1980 at the relatively modest level of $30 million a year, rising to $630 million a year by 1987. In all, more than $3 billion was funneled to the Afghan resistance.
If Bin Laden and the Saudis had such irreconcilable goals, why is there a whole line of thought blaming Saudi Arabia for his brand of religious extremism, and indeed, for enabling or resourcing him?
I've wondered if alleged Saudi support for OBL was something like New England liberals and abolitionists funding John Brown's anti-slavery crusade in antebellum USA. That is, the funding isn't coming from the government per se, in fact the US government and Brown hated each other, but rather it was coming from well-connected individuals who could probably be considered part of the "Establishment" of its day.
But if you're a paranoid slave-state settler in Bleeding Kansas, the difference between your violent nemesis getting money from the government, and money from high-society types who go to all the best parties in Boston, might seem negligible.
(Not that I would otherwise compare John Brown to OBL.)