Or because they liked the colours for aesthetic reasons haha.
Also choosing a cloth colour has nothing to do with thermal mass and everything to do with absorbtivity/emissivity/reflectivity aka material properties affecting radiative heat transfer.
In any case, shirt colour has a small effect on temperature, maybe a 5°C (at most) difference between white and black, according to some studies. So unless you're really chasing the most optimal clothing, it's best to just wear what makes you happy.
What exactly did you not like? Using it now and it's come a huge way in just a few weeks. Of all the apps I've tried it had the most compact and quick interface.
I feel people had a lot of loading issues when instances were going down left and right which gave Jerboa an unfair reputation through no fault of its own.