Earlier quoted context omitted.
When you buy a mined diamond, you are paying for the story, of it being a finite thing, formed in the earth over a very long period of time. Lab grown diamonds don't have that story. Separately, the work that goes into cutting/finishing diamonds is incredible and there is a huge amount of variety between individual diamonds. They are very fascinating things.
That sounds like industry apologetics, to me. I don't know that the population in general are that keen on geology.
I think it's quite common knowledge that diamonds were traditionally mined before we were able to make them in a lab, and because of this it's seen as the default to which any other methods of making a diamond are compared.