Yes this is a real problem and it's not just Facebook. Designers are often young and typically have very, very good eyesight, much better than the average population.
Out in the real world, the average young person probably has good eyesight and the average middle aged person has so-so eyesight and older people generally have crappy eyesight.
But then there are lots of people of all ages who have poor vision, weird quirks, colour blindness, tunnel vision, or clinical blindness.
Arbitrarily reducing a font from small to teeny is basically a slap in the face to anyone with less than perfect eyesight.
Yes, a user can adjust their browser settings to enlarge the fonts but when you do that to Facebook, for example, it makes all the text larger and the whole thing looks like shite.
Out in the real world, the average young person probably has good eyesight and the average middle aged person has so-so eyesight and older people generally have crappy eyesight.
But then there are lots of people of all ages who have poor vision, weird quirks, colour blindness, tunnel vision, or clinical blindness.
Arbitrarily reducing a font from small to teeny is basically a slap in the face to anyone with less than perfect eyesight.
Yes, a user can adjust their browser settings to enlarge the fonts but when you do that to Facebook, for example, it makes all the text larger and the whole thing looks like shite.