Somebody chose to pay the IPO price. Nobody could've offered to buy at that price, or interested parties could wait for the price to fall (if the party felt the IPO price was unreasonable). Typically, the underwriters will ensure there's interest at a given price range, prior to the listing. The demand was there.

I place some blame on the companies (and it is their responsibility to list potential risks in their public filings), but also it's somewhat the fault of buyers who scooped up millions/billions dollars worth of shares at sky-high valuations.