I think it is to give the fighters rough equivalencies, but I really have no idea.
I tried a more tactful approach, but I see that it failed. So, I'll come on out and say it: that "for those of you who may be new here" post in the fighter poll was directed at you Woolie. Go read it if you haven't yet
And please, PLEASE stop talking about things in terms of hitpoints or other table stats. I am a modder myself, and not once to I describe my ships (which are table mods as well as models) in those terms. A cruiser may have 70000 hitpoints, but I say that it is as tough as a Leviathan instead of providing that number. No one cares, it all depends on how it plays not how it reads. Go read the Freespace Modding forum, look at some of the older posts and the WIP's. If you have a comment about one of them that hasn't been said already, say something. Those topics are not so numerous as these, so you may end up bumping an old topic, but we can forgive a few of those if it is important or even positive and productive.
EDIT: Ok, seeing as you have started to do your research and have apparently voted in some older polls, lets add one more qualification to not minding you bumping things. If it hasn't been posted on in 2003, leave it alone.