I think the smug punky attitude can apply to anyone who has a label they have to live up to. I quit summed it up for the JW crowd. I can't tell you how many conversations I've had with "the friends" where there was a constant game of one-up-manship in regards to spiritual goals, spiritual accomplishments (which are really organizational accomplishments), and knowledge (I hate feeding the speaker, imagine an entire table of people outdoing one another with what they know, speaking with food between their teeth). That same attitute carries over outside the hall.
For the record though, anybody with a label they have to live up to can present the same smug attitudes in other walks of life. Think about the outward conservatives overusing words like, "liberal" in a negative sense. By the same token though, I can point you to the bisexual employee at Starbucks who can't understand why you don't appreciate Radiohead as much as they do.
I think everyone has an overflated sense of ego at times, some worse than others. I noticed on here, the ExJW's arent as bad, but I did notice some of the ones who I believe were never JW's have a certain superiority element in their posts. The run of the mill Trinity threads can be an example, although I won't mention names. (let the reader use discernment!) At the same time I don't want to judge to harshley because you can't sum up a person's character entirely based upon what they post here.