>Why did you take a piece of BSD licensed code and put a GPL2 license
> on it? Is that even legal? I just don’t understand this at all

Well, download Medusa sources:

and read its LICENCE.txt, which states:

“Medusa was once distributed under a ‘free for non-commercial use’
license, but in May of 2000 Sam Rushing changed the license to be
identical to the standard Python license at the time.”

So, there it should be legal to licence derived work under the GPL.

Also, if you care to have a look at Allegra sources you’ll see that I included Sam Rushing’s copyright and licencing term wherever the original sources remained allmost or entirely unchanged (only five modules out fifty).