I agree with that. In my ideal world, the person who said "evolution is just a theory" would hear the scientist explain the difference and think "Ah, using the word 'theory' like I have before is maybe not wrong in some contexts, but it's causing confusion and in that sense it weakens our language. I will therefore be careful and use another word instead, perhaps 'speculation', to sharpen our shared language into a more precise tool for understanding each other. Since words mean what we all agree they mean, they are infinitely malleable and beautifully fragile, but we all have the opportunity, and duty, to influence the direction as we head into the future."