The Romans who had arrested and tried and executed Jesus were seen only as pawns in the hands of the Jewish leaders. It is not the Romans who are blamed, but the Jews. It seems to me that part of the point is for us to look at our need for villains to blame for the things that go wrong in our lives. We are continually searching for explanations of why bad things happen. Bad things have always happened, and they probably always will.
Innocent people die.
Loved ones die. We are stricken with illnesses. Madmen, terrorists, slaughter the innocent. Presidents and Prime Ministers who seek peace are assassinated. Innocent children in a kindergarten classroom are murdered.