Well, this isn’t a bug but a styling choice for the theme that has been there since almost since it’s inception 7y ago!
I don’t know what the reason behind the choice was, but I think the theme page where you brought up it as well, is the appropriate place to ask for it to change, and so I’ll be closing this topic.
If you would like to change this on your personal forum, I would recommend making a small theme component and adding: