If my kid goes into the kitchen, and I go in a little while later and see the cookies are gone, i'm going to believe they ate them. Am I 100% convinced of it? No. Maybe i just didn't realize they had been eaten earlier, or maybe someone snuck in the back and ate them. But I'm relatively convinced they ate the.
I'm sure there are very few people, at most, that are convince 100% that Boeing did it. But it's very presumptuous to assume that all of the people in this thread claiming Boeing did it are just joking. Seems more reasonable to take their statements at face value and understand that they do think Boeing did it, or at least someone related to boeing did it.
But I'm not sure what this has to do with what was suggested by your initial post.
Ps deductive reasoning doesn’t mean “I know it for a fact”
By definition deductive reason is using logic to come to a specific conclusion, so it absolutely does mean it's a fact.