The BSD license is why we have Valkey and not a purely closed-source Redis. It would have been much easier to perform the rugpull if Redis had initially been GPLed.
And how exactly did the BSD license make creating Valkey easier? GPL and BSD licenses both have the source in the open. Anyone creating a fork, can easily do so for either BSD or GPL licensed projects. Since Redis is a database, which the user won't be using a binary of, even using a fork of a supposedly GPL-licensed Redis would not require you to share your modifications with your user, same as BSD.
On top of badreligion42’s point, that both licenses allow forking just as easily - don’t you have the rugpull part backwards?
Afaik BSD licensed stuff can be re-licensed under any more closed licenses at any time, where as to re-license GPL, you need consent from every single contributor.
But i’m not familiar with the redis-valkey story so, maybe there is some nuance i am missing?