Because they lobbied for a rule change to get fast tracked to an index forcing passive investors to buy it at IPO price instead of being included after market value corrections.
This is completely wrong. Passive funds don't buy at IPO price. They buy after the inclusion rebalance which happens weeks later, at whatever price the market has already set. Plus the S&P500 rule change hasn't even happened yet, it's unclear if the rules in the current form will go through.