I would say mostly because it's a very small religion (with only 1500 adherents), predominantly practiced in Lagos, Nigeria. For the vast, overwhelming majority of people living in the United States, it's neither a potential mission field, nor a potential threat to their own faith. Therefore, its relevance to the people sitting in the pews is not very high. While it is laudable to try to help those in any false religion convert to Christianity, I don't think that a fascination with such a small religious group is particularly useful, unless the group is growing rapidly (which Chrislam is not), an active terror cell, or a horrendous hate group with a reputation or ability to cause harm far outstripping its small size (again, Chrislam is not either of those things).
Most pastors do and should focus on things more relevant to their congregation, like helping them to grow in their own faith life. When evangelism is mentioned, it should focus on what the congregation members can actually do, rather than simply on the evils of a small group entirely and likely perpetually isolated from everyone in the audience. A dictionary of syncretic religions could include Chrislam for educational purposes, but such a minority group should never be the sole focus of an entire sermon or homily, especially when there are other groups more relevant to the people hearing the message. I worry that the current fascination with Chrislam has more to do with a media-provoked fascination with Islam than with anything else, because as it stands, this group is only about three times the size of
Nuwaubianism, and less than a fortieth the size of the
Raelians, both New Religious Groups with beliefs much more destructive to Christianity, but many people don't even know that those two exist.
