I think people should absolutely be concerned about their trash and the disposal of it. The last thing I want is the campground to actually look like a dump. As for putting trash out front and wait for pick up, that's fine as long as people put it out between the stated times you are supposed to, and many don't adhere to that. They will just put it out in the evening and let the critters get into it and drag it all over the CG. Then they wont lift a finger to pick it up when they know it is their trash.
Some people may not care if there is trash all over, after all, its not their property right? I happen to care. I have taken bags and picked up **** that is just laying on the ground because I care. I also think more campgrounds need to have recycle bins and make it clear that they expect you to recycle what you can.
I hate it when people use the fire ring for burning their trash too. I have seen some pretty disgusting fire pits from people dumping their grease in them and all sorts of things that should not be burned, like plastic. But of course, they will be leaving soon so to hell with the guy behind them coming into the spot. Its obviously too much to expect that people care about properly disposing their trash and leaving a site clean for the next person who uses it.