They aren't all usernames of Noobstown players, just the first few. I assume that someone has simply gone into our members list (which is freely accessable here:
http://www.noobscraft.com/mlist/ when logged in) and copied down a number of users, or it might be that the player was simply collecting names of those who connected to Noobstown on a specific day and those are just the users who did so, thus explaining why you are not there.
Whatever the reason it is unlikely we will find out why you aren't there Jayjay or why you are 58th Fire
, but it isn't something you should be particularly worried about, there are hundreds of ways for a list of Minecraft usernames to be generated.
I'm more interested in how you came across this list to be honest.