[boguslav]

That's easily explained: jealousy. Slovio was the only Slavic-based auxlang available on the internet for a few years. However, it was not received well among Slavs, who found it too artificial (Slovio is basically Esperanto with Slavic - mostly Russian - words), and thus it became a complete failure. When Interslavic was initiated as a more naturalistic alternative, the author of Slovio first tried to ridicule it, and once it became successful, he started claiming they had stolen his idea and propagating Slovio under the name of Interslavic. Both languages have absolutely nothing in common, except that they are both based on Slavic material.

That was years ago though. Slovio has been dead for the last eight or so years.