I see your point, and think one of the merits in OP's argument is precisely what you're saying: words have meaning, and saying something like "I think that X is probably the case" when you're virtually certain that X is the case dilutes the meaning of words.

That said, I think throughout the post OP is mixing different dimensions of communicatiom together in a way that confuses the conversation - namely conciseness, directness, and explicitness - which while often overlapping aren't exactly the same.