Isn’t praying for the dead just superstition?

We do not know what God’s judgement is on any particular soul. We know only that it will be a judgement of love. Our prayers prevent us from being inquisitive or superstitious about those who have died. Being inquisitive was what got Adam and Eve into trouble, and for us to have trivial curiosity about the dead is contrary to God’s will. More than that: it is extremely dangerous.