Personal attacks are a perception in the mind of the beholder. There are some things we can all agree on as being personal attacks. Others we will see in different ways.

Doug was implying that the liberal-minded people here (meaning those he doesn't agree with) are forever raising a big hulabaloo about absolutely nothing and "crying wolf", as he sees it. Greg finds Doug's attitude snide and irritating.

And it is a bit snide and irritating, isn't it? ;-) It's a contemptuous dismissal of something that concerns a lot of other people.

Whether or not it's a personal attack, however, is a matter of perception, as is your opinion that Greg's response to it is a personal attack.

I think someone could make a good case that neither of them made a personal attack...or that they both did. Depending on perception.