The problem is that it causes confusion. This discussion began with "conspiracy theory", and the use of the word theory here implies to poop and cocco "unproven", while you're saying that the word "theory" in a scientific context means the opposite.Just listen to what people are saying and try to hear their intended meaning. Anything less is not communicating in good faith.
Also, if we have different ideas what a word means, we're not actually talking about the same thing.