The only way futures trading changed the btc prices is that it reduced the btc potential price growth.
How did it reduce bitcoin's potential growth? Like what this statement said:
futures are only limited to a limited number of people from a limited country not the whole world and people aren't all using futures specially because of taxes.
IMO futures is just a means for bitcoin to attract institutional investors that will help reduce price volatility by multiplying bitcoin's real world use cases. Also, bitcoin futures is only a contract used to buy or sell btc at a specific future date and price. It is only like a bet(but removes the risk of holding btc while speculating). It might lessen the demand, but it will not impede bitcoin's price growth.