I'm guessing @Yehuda did it that way because of the secondary threads that appear in the list (and here.)
Actually, nah. For most of the "and here"s I couldn't decide which one was more "master" than the other, so I just chose one.
I did Master Thread on each one for OCD purposes. I thought it looked organized. Get rid of it and leave it as "Southwest, United, United Club, etc" if you'd like. That wasn't important to me, getting it stickied was. And that doesn't look like it's happening.