That is normal as far as if there is only one person in your category you are the winner by default. That is why they have OverAlls. If you win by default you still have to look good for the overall spots.
Also physique shows are a place for people to show physiques they are proud of. We can't go getting all elitist and say someone who lost 100lbs but isn't ripped yet shouldn't be allowed on the stage. So long as they don't win out of sympathy, just getting on stage is their reward to themselves for the big weight loss.
Not being a dick here, but if a person pays to compete they should get to compete. You honestly think someone should have to go through prep only to be told that they can't compete because no one else is in their category? That is more about the competitor than the competition. You don't rob someone of an opportunity they busted their ass for just because no one else showed up. Imagine you did a 16 week prep paid for a coach, posing lessons, posing trunks, hotel, spray tan, and after that 600-2000 you spent the promoter says. Sorry you wasted your time, money and effort but you are the only person in your category so you can't compete but come back in 3 months and we will let you for free...
Sounds like you guys are thinking more about being entertained and seeing what you want to see at a show. Not what the competitors are there for and if their need / desire to compete is being met. Keep in mind the competition is for the athletes participating, and not for what the audience wants to see. You are simply a voyeur at that point. The only entertainment is the guest poser. Everyone else is competing or fulfilling a personal need on that stage.