Why is the font size so tiny?

[klapstul]

The font size for text bodies is set to 10px. Not pt or in, but px. While I admit I haven't fully understood the difference between each, I know this is very low, urging me to set the zoom to 120% to make the forum usable, so please, why do we do this?

[sunrat]

Forum probably looks fine on a 1024x768 monitor. It's not a problem when text size is customisable. Mine is at 133% for this forum on a 1920x1080 screen.