Not quite sure how anyone considers spawn camping, on dustbowl no less, lame. First and foremost, for a spawn camp to be effective at all, the enemy has to make it there early during the round, typically before the first point is capped. This means that:
1. They have to use an uber to get there, this is a sacrifice. If your team doesn't follow the uber to disperse of them, that's bad play on your teams behalf.
2. They have to sticky jump, thus sacrificing health to get there, if no one notices a demoman or soldier doing this, again this is bad on your team.
3. Spawn camping is nothing more than stopping enemy reinforcements. What are people who make it to your spawn supposed to do? Plant stickies 10 feet far from the door so you can see them first? Just because it rages you, shouldn't mean anything. Demomen can trap any part of a map, they don't give you warnings first.
4. Dead ringer spy, put up DR, walk out, cause him to detonate and be on constant lookout for a Spy. In this case, your team will have a chance to progress because he will be focusing on you.
5. Bonk scout. Scouts are the Demos hard counter, he beats you in that situation, tough luck.
And finally, what exactly do you think red does to blu on the first stage of dustbowl? Additionally, do you think red would have any problems whatsoever on say, 2nd or 3rd stage, pushing blu back to their own spawn and camping it?
TLDR: If you allow a spawn camper to get to your spawn, he deserves the several kills he gets. If your team seriously can't coordinate against one demo, you deserve every thing you get.