Why are people discouraged when thinking about getting a GSD a their first dog? I think it may be because people are surprised by the amount of time/work/money required but don't those apply to all dogs in general? Is it mostly because some can have dominant tendencies? Thank you.
The warning should not be taken lightly. Dogs have different abilities and needs and owners must learn and respect these. While you are correct that these needs apply to all dogs, the degree varies a lot and the repercussions of failing to meet some dogs needs is MUCH higher.
I have had dogs my entire life including field Labs, Spaniels, Beagles, Terriers, and various mutts. I also now have a 6 month old working line GSD with high drive. All dogs need to get exercise and interaction, but the GSD is a whole different ball game.
My GSD is the most intelligent, loyal, and fun dog I've ever owned. He is also the most demanding. I run him an hour every morning before work and he gets up to another hour of training and play per day. If I have an early meeting and cannot run the GSD before work, my wife is in for a heck of a day. Thankfully she stays at home and our kids are home schooled so they can still play with him and take him for a walk (but that alone is not close to enough to satisfy his work needs). His pent up energy will drive him (and others) crazy as he runs through the house and tries to play with everything and everybody. Putting him in an exercise pen can provide the family with a little relief but it's also depressing for the dog who needs more activity. He is exactly what I wanted in a dog, but for the average person who is not going to put significant time into their dog every day, he would be a disaster waiting to happen.
I also currently have a Lab and Terrier. Neither require more exercise or stimulation than a 15 minute walk and a little bit of tug or fetch. The difference in their needs is night and day.
A GOOD breeder will identify puppies personalities and match them to the type of family they are going to, but just as there are a lot of bad/uncommitted dog owners, there are a plenty of breeders that are not so great either.
Further, a dog without structure and discipline will be naughty because they are bored and lack respect because they've been indirectly taught that's ok. Evidence proves that the VAST majority of people are willing to put very little effort into their dogs. How many little dogs do you see out walking their owners, pulling on the leash, barking at everything while the owner appears confused and distraught trying to control them while (maybe) offering an apology and excuse? I see them every single day. Do you think they thought to themselves when they first got the dog that they would intentionally be bad at giving the dog exercise and training? I doubt it, they were simply unrealistic. Imagine if these owners had a high drive 80 pound GSD? They would probably be hurt and/or sued in short order.
Most first time dog owners simply have no idea what they are willing to put into a dog. Romantic visions of playing ball in a field and hiking those trails each day quickly fade after the dog has chewed their furniture, dug up the garden, pooped on the floor a dozen times, and demands to go for a walk in the rain after their owner had a long day at work and just wants to watch TV. It's far better to start with a lower-need dog where overestimating your commitment will not cause an animal unnecessary stress and possibly cause a dangerous situation. If one finds out they love working with dogs, has the consistent time to invest, and gains some experience training, then they might love stepping up to a dog with more capabilities (but more needs).