You can try mozilla.accessibility newsgroup. Unfortunately, there is
little activity in the group (the last post is someone complaining about
it).
You can also look here:
https://wiki.mozilla.org/Platform/2013-Q2-Goals#Accessibility
That won't tell you who to contact though. I understand your problem and
frustration. I was an extremely nearsighted contact lens/progressive
glasses senior with cataracts and had to use large fonts in past years
with lots of pages like you describe. I then had cataract surgery and
got premium lens implants and now use 13pt font (and no glasses or
contact lens at all needed unless tiny print in poor light) but am still
worried about buying a new monitor (mine is almost 10 years old) and
getting a widescreen 24" one and needing larger fonts and if I will then
experience display problems at many sites. Even at 13 pt minimum font
size on Fx 17 ESR and Sea Monkey 2.17.1, the National Weather Service
page for my area displays with text on top of text in several areas. I
have to reduce minimum font size in both browsers to 11pt to get the
page to display properly and this is on a 19" LCD at 1280x1024.