Yikes! That sounds like on par with most retail experiences...I'm glad you're getting away with that. I think a big problem is that most managers themselves aren't really trained on how to be managers...if they get any at all, it isn't enough to make a big difference. I've read a lot a lot of material on leadership, business culture, and management, and I wouldn't say I'm great at it...but I'm sure I've seen more on it than most retail managers. Plus it's a stressful workplace and managers will have a tendency to say anything just to keep things going.
It's been shown that employees are more motivated by appreciation and encouragement than by raises and benefits, and the books I've read make sure to point out that appreciation doesn't cost the company anything. Where it goes off the rails is that a lot of times people use appreciation cheaply and shallowly. There used to be someone in leadership where I work that would go around telling people 'Thank you for doing that', without usually even knowing what they were doing or why it's important. And it feels cheap and patronizing...so I try to make sure when I give praise and appreciation, it's really for things that deserve it. Though sometimes I get accused of the exact opposite...that I don't give enough appreciation and recognition, so... 
Actually, Walmart specifically has something called the Academy, where all members of management (salaried and otherwise) are sent at various points in time to get continuously trained how to be a good and effective leader. But you have to remember that promotions for the wrong people are basically reasons to have power/ego trips...and Walmart for some reason just loves to promote the wrong people. They won't care if method A is more effective, because they're the ones that can give out orders, so they'll do it their way...and only compromise if and only when a higher member of management tells them otherwise...because they're also likely schmoozers that kissed a lot of ass to get to that position. But once that higher manager leaves, it's back to the old way.
That's why Regional/Market walks were always a nightmare. You'd see all of the managers go into panic mode and suddenly follow One Best Way (Home Office's set of codes to run the store effectively) to a T when they were barely following it before. And because they know they have to completely alter their methods, they go into almost full attack mode on associates to get things done. But once the walk is over, they go back to running things their way.
And that's really the thing. As I said, words of appreciation are more tossed around to give the illusion of value because there's an understanding that "If they hear it, they'll fall in line better." But when you hear it on the constant, yet the same person saying it completely contradicts those words by their actions...then it becomes simply a shallow and cheap device, as you said.
When I mentioned those things earlier, those are when I really felt appreciated. When my DMs when I was in electronics sat with me and made sure I was okay after both when I heard my grandma was in the hospital and after I learned she passed (because I was a mess both times)...that was when I felt like I was actually appreciated, because they genuinely cared and worried about me. It wasn't just sitting there and giving me the talk of "If you need to leave early, you can." They sat there, asked about what she was like, gave me hugs (the female DM was actually close to crying with me), and it was moments like that where I don't entirely regret the fact that I worked there.
But that was usually it. I never had issues with the hourly managers (minus a select few including my most recent DMs). Aside from Shelly, it was always Salaried management that gave me the most grief because of their double-speak, their condescending attitudes, and their non-hesitation to criticize or berate right in front of customers.
