"pedophile" refers to someone with primary sexual attraction to children, whether or not they act on that attraction.

Terms like "predator", "molester", and "abuser" refer to someone who takes sexual actions against children.

There is overlap between the groups, but they're not identical. There are celibate pedophiles, and pedophiles who have ordinary adult relationships and keep themselves away from children. And there are predators who aren't specifically attracted to children, but instead are attracted to the power imbalance.