I think there is a balance to be found between "pinkifying" and "de-blueing" (to wrangle an inversion out of that word). Many of these early education coding platforms use "play" to introduce fundamentals and concepts to kids. They're not intended as formal platforms for computer science education; they want to let kids do cool things and get excited about programming and possibly ramp up into that more formal programming education.
Letting kids manipulate characters from properties to which they've already been exposed is a good way of creating that initial interest. The issue is that assets like Minecraft Steve, or R2D2, or things like that, while obviously loved by no shortage of girls, are still primarily marketed toward boys. Until we can effectively move that needle at a higher, more societal level, I think it's valuable to incorporate media properties targeted toward girls into these kinds of platforms simply in order to engender that initial interest. A kid (regardless of gender) who loves BB8 should be able to use their learn-to-code-platform-of-choice to make BB8 run in a circle. A kid (again, regardless of gender) who loves American Girl should be able to use that same platform to make Julie say something funny.
My company has been doing some work with the Girl Scouts, teaching girls to build games and apps in Augmented Reality, and while the interface/platform itself is sterile and professional (& obviously if you think theming an IDE pink will help "appeal to women," this is an issue), the girls naturally gravitate to characters and assets from the properties to which they are already exposed and are already fans. This includes everything from Minecraft Steve, to Spongebob, to lolcats (which are, apparently, still a thing) to Elsa, and Barbie.