German ß very wide

[SolidTux]

To my eyes, both the small and capital ß look too wide. Here is a comparison with some other fonts (here is the project):

Scaling the small one to 87.5% and the capital one to 75% looks more like what I'm used to:

Is this a design decision? Could this maybe be switched with a font feature as it's not easy to switch the width of a certain character in all programs?