> Android device where the vendor chose to ship some brand-specific UI font
Chrome (and Android Webkit) hardcodes Roboto as the system-ui font (in such a way that both Samsung and Xiaomi devices (which both have font options) cannot touch), and Firefox brings its own font rendering which also hardcodes Roboto.
If the system-ui font of Linux is set to a silly one (according to your opinion), then the user-in-question would realise that they are the one who picked that font that you called silly, in other words they don't care about your opinion at all.
Chrome (and Android Webkit) hardcodes Roboto as the system-ui font (in such a way that both Samsung and Xiaomi devices (which both have font options) cannot touch), and Firefox brings its own font rendering which also hardcodes Roboto.
If the system-ui font of Linux is set to a silly one (according to your opinion), then the user-in-question would realise that they are the one who picked that font that you called silly, in other words they don't care about your opinion at all.