My problem is I have a scientific background and appreciate little details like evidence and logic before jumping to conclusions that serve to reconfirm my world view.
Scientific method is fine for the natural world.
The world of humans is much more complex and messy. Lots of things happen underground, hidden from public scrutiny. Intentionally hidden.
It would be foolish to assume CIA or MI6 or Putin are not cooking some crazy projects right now, just because we have no precise scientific evidence of their shenanigans.
The public knows maybe 25% of important events/decisions, at best.
Occam's razor is still a very good tool.
If we go back to 9/11, again, the "motive" for a conspiracy behind that event is supposedly the war(s) that followed. Explain to me how it makes sense to fake an attack and announce most of the terrorists were Saudis, if your goal is to attack Iraq ? Saudi Arabia is still an ally to this day.
There is no doubt that plenty of unsavory people wanted to attack Iraq, they said so publicly, wrote books about it, etc. If they had wanted to create a good reason to do it through a terrorist attack, though, 9/11 doesn't make sense. And indeed it didn't work, they then had to cook up the WMD story (a proven conspiracy).