If Halloween was a Christian festivity, how come Catholic countries such as Italy never celebrated it in the way the USA does?
The word Halloween comes from the traditional Catholic feast “All Hallow’s Eve,” referring to the Solemnity of All Saints. Here in the United States, the celebration of Halloween includes trick-or-treating. For more information on Halloween, including its origins, see these various Catholic Answers resources, and also this tract from Catholics United for the Faith.
One obviously shouldn’t glorify the darker side of the modern celebration. But instead of turning off your porch light and not giving out any candy, why not instead provide treats and say “God bless you" to the children who knock on your door? In other words, take back the night.
And you can also make a point to praise those kids in holy costumes and make light of those dressed as bad characters, including the devil. For example, you could say, “Something tells me you’re a good kid and wouldn’t do the devil’s works.” Or, if someone is dressed as a ghost, you could say, “What’s really great is that we have good angels and saints watching over us.”
With a little creativity, you can turn Halloween into an occasion for evangelizing. After all, on what other night are you going to have all kinds of kids—and their parents—knocking on your door with smiles on their faces? Providing them candy gives you an entree into sharing the gospel with them.