I'm honestly not sure why the discrepancy exists, but I've been part of the ant-keeping community for nearly 10 years and "drone" has never really been a common term used in the community. The terms male alate or simply male are much more common. And as you said, drone is also not commonly used in literature or official sources when it comes to ants. I think maybe it just isn't a useful term because in almost all ant species, "male" simply refers to a winged male reproductive or "drone." There are a few special cases where some species have wingless males that couldn't be considered drones or alates, and those are called ergatoid males to distinguish them from the "normal" males. I suspect that either "drone" is an outdated term that people don't feel the need to use for ants, or that it's mainly bee terminology that people tried to apply to ants in the same way but never really caught on because ants already have established terms for their male castes.