As one of those on FR older than dirt, let me say there are mean girls... And mean guys... Crap, there are just mean folks out there at all ages!
Those 'mean' high school 'cool' girls will most likely grow up to be mean... No, make that bitches. I saw them in high school and I saw them in college and in the disco clubs, C&W honky-tonks, in the business world and I see them nowadays in the "express/cash/credit only" lane with more than 10 items and taking forever to write a check...
And they are not only females, they are males also.
The world is full of A**holes and even here on FR they show their ugly ways and views.
I don't worry much about them because in life, as it is here on FR... Those I like I find I spend time with... Those I find of the 'mean' persuasion, I generally ignore or give a terse reply post to... And then forget them.
One nice thing about being older than dirt is I don't have to suffer fools anymore... And I don't!