Are Americans superstitious too?

These are rituals, not the same as "superstitions".

Believing in anything without understanding the true principles is "superstition", but believing when you understand the principles is not superstition.

Many Americans believe in Christianity, and they really understand the principles, so they are not superstitious. Of course, there are also those who do not understand the doctrine and follow the crowd, so this is "superstition".