From the FSF's own list of GPL-compatible licenses:

> License of Ruby (#Ruby)

> This is a free software license, compatible with the GPL via an explicit dual-licensing clause.

... yes? That was my point. They switched from a GPL-like license to a BSD one.

The dual-licensing nature of the Ruby license has always meant that you could distribute it in a BSD-like fashion (with an extra restriction on naming). They simply moved the "or" part of the license from GPL to BSD. Ruby was never distributed in a GPL-like-only fashion. The changeover is mostly a non-issue.