I don't know if it means they are strong but it does seem to yield good results more often than not which therein lies the problem. I have worked with customers and the ones that are rude, obnoxious, and loud seem to get their way. The ones that are classy as you say get shoved around. But in some stores, you don't have to be confrontational. However in some other stores it's not that simple. For example, my husband and I got loud in a store because my stepdaughter needed to return a pair of jeans. She had the receipt. The jeans had never been worn. It had only been a week. They wouldn't let her return them. It would mess up inventory. The manager and employee were being rude and unaccommodating. They were wrong. I got a call from corporate saying that they should have taken the exchange and they apologized that we were unable to. Arguing and carrying on was not fruitful but it was frustrating to us. We didn't like how they treated her. She's 13 and they took her receipt. She initially went on her own.
There was another time at another store. We were right but the employees were being difficult.
I hear what you are saying but it comes down to training quite often. It's not always that customers are obnoxious. Sometimes yes, but not always.
edit: The most obnoxious people are the ones that have money because they are used to getting their way no matter what. Most of the time I'm pretty quiet and calm but if something doesn't make sense then I'm going to continue arguing the point. My stepdaughter should have been allowed to return the jeans. It was that simple. I could see if there was a problem with them but there wasn't. What would you do in this situation? The employee (not the manager) threatened us. The district manager told me that he was going to speak to her about it. He called me as well to apologize. Maybe it's not so much the loudness factor but the irrationality of some people. I've had to deal with it. Those are the people that irk me. I have nothing but empathy for the people who make rational arguments. I would not argue with them. I would say, I agree but unfortunately, there isn't anything I can do. The manager and the employee wouldn't say that. They were there is nothing you can do. You'll just have to buy another pair. Honestly, if I was the district manager, I would reamed them for their behavior. I told him everything.