I'm of two minds of this.
One, bootlegs of current stuff is just going to lead to some dumb parent getting lead poisoned kids because they wanted to save money, and crack down on all of this, so Lepin should be more careful about selling those. Sure, they have no reason to, but all it takes is one dumbass to ruin it for everyone.
On the other hand, for discontinued sets, especially if you let people know 'hey this isn't actually Lego proper', and people don't care and just would rather spend less on old sets than they do on rent... yeah I see no problem with doing it. Why the fuck would I want to buy a Lego Carousel for 3000 dollars, especially if none of that money's going to the people who made it but rather to one hoarder in Florida, or just send 80 bucks to China for a near-genuine article? And yeah, that could be a scam too, but it's easier to justify rolling the dice on 80 bucks than 3000.