It seems like the discourse has shifted to describe even legitimate businesses that are overvalued in the opinion of an author as "pump and dump" or "ponzi scheme"
That said, it looks Beyond Meat made money in two quarters last year. So not a good fit on those criteria.
Which is the whole point of YC. IPO over valued companies and dump it on the retailers while cashing out your chips. Never mind the structural dangers cheap capital pose when the cycle winds down.