Such a person might do this privately or might seek out a group of people of similar beliefs, and they will strike out at their perception of evil together. The evil being those ideas and thoughts that are objectionable to their belief systems, but are still part of the thoughts arising in their minds and those of others. When certain thoughts don't fit our images of good and proper, we sometimes isolate them. They can grow during this isolation. They become a part of the unknown.
Most belief systems have a dumping ground for unacceptable ideas.
There they are seen as manifestations of the Devil. To them hell doesn't exist. There are always ideas transcending our belief systems. It is up to us to decide what to do with them.