The reason some might think this is because if Romeo had never fallen in love with her or talked to her, people would never have died or been killed. Romeo quickly falls in love with Juliet. They got married one day after meeting. Nobody knew they had gotten married. The only person who really knew was Brother Lawrence. He was the one who married them. The public knew they were married but their families didn't know. Romeo was crazy about Juliet. Some people might also think that it's Romeo's fault because he killed Tybalt. After killing him, he was banished from Verona. The Capulets and the Mercutios didn't get along at all. Perhaps this is why Romeo and Juliet died. They never had a good past. Maybe if they got along better, they wouldn't have had to hide their marriage. If they didn't have to hide it, they wouldn't have found themselves in this situation. Some people might think that if they told the Capulets and Mercutios it would change the whole story. Maybe Juliet wouldn't pretend to be dead if she told her parents about Romeo. If they had been honest about it, audiences might think it would change the entire theme of the film.