In my understanding some index funds i.e. FTSE Russel ones will include spacex with the weight based on the floated stocks, so in practice the weight in the index will be small enough in All Cap etc indices. So I decided for myself it is not a cause for concern. But I think now it is the time to look for index providers who do not decide to bend the rules for short term gain (i.e. S&P and Nasdaq).