This is a more honest and realistic take than most on the thread. Note that either way it's the provenance behind the gem that you find attractive, much more than any instantaneous quality of it like chemistry, lack/presence of defects, etc. It's the story.
It’s not only that. Lab diamonds are superior in every way I’ve heard of. The emotional appeal of their provenance is the sole remaining reason I’ve heard people claim that slave diamonds are superior. I contend that they’re worse there, too. In fact, the only reason I can imagine someone preferring mined diamonds is that they genuinely value the human suffering that goes into them.