This is true within the context of "science". Most dictionaries have secondary (or tertiary) definitions of the term more in line with how "lay" people use the term - like an explanatory idea or principle. "I have a theory about why Pearl Jam was more successful that Stone Temple Pilots in the 'grunge' era" does not use the term "theory" in the same context as "The theory of evolution has been supported by findings in a variety of scientific fields".

There should be distinction between the colloquial use of the term and the technical use of the term. I have seen the same issue with the use of the term "cause". For a Fire Investigator, the term "cause" has (or should have) a particular meaning. For the layman, the term (although "incorrect") may be different. When a reporter asks for the cause of the fire, they are probably not thinking of the circumstances, conditions or agencies but rather the shorthand description of either (1) the ignition source or (2) the classification. While we should try to educate them, their use of the term is in a different referential frame.

I have a theory on why people use the term "theory" when they really mean "hypothesis."

Steve