Do you develop on GitHub? You can keep using GitHub but automatically sync your GitHub releases to SourceForge quickly and easily with this tool so your projects have a backup location, and get your project in front of SourceForge's nearly 20 million monthly users. It takes less than a minute. Get new users downloading your project releases today!
And just because "they can come back and register with false information," is that any reason to let persons who have registered with their real information stay?
Actually, I would think that is a very good reason to let them stay. I'd rather have them there under their real name than a fake one.
This is ignoring my opinion on the sex offender list in general.