Neither the tag history nor the tag excerpt history back your initial belief or premise that this tag was primarily meant for Ruby. I won't deny the odd question here and there, but it seems like that use was usurped and then codified by someone adding that tag usage and description for it.
Since it seems like most of the questions in the beast tag are meant for the BEAST attack anyway, the path of least resistance would be:
- Create a new ruby-beast if it doesn't exist (good luck - it doesn't seem like this project exists anymore...)
- Edit questions which are explicitly about Ruby and the Beast forums and also have been tagged beast with ruby-beast
- Add a descriptive tag wiki and tag excerpt to the ruby-beast tag.
Creating a meta post would've been the better thing to do, as reviewing changes to tags or making tag-only changes can be finicky.