You see all those people in chat also shouting "lfg"? That means they, too, are looking for a group. And you are entirely free to invite them to your own party and start your own group. Take some initiative, eh? Hells, if you really want to be bold (or irritating), just scan through the list of players in the instance and invite anyone that's not already in a party. Additionally, pretty sure anyone you see around with the yellow triangle-in-square icon next to their name is someone running solo, and you're free to try inviting them as well.