There aren’t any separate queues in classic.
Obviously everyone is allowed to play bg’s and those twinks have nothing to say.
They play their super pimped out twink because their main sucks and they want to feel super strong against other low level players/victims… They don’t want to have such victims in their own team.
Anyway all brackets are full with twinks even the 59 one (!). Some lvl59 twinks get help from their guilds to get some epics that they can already use before 60 and then they try to rank up in the 59 bracket.