I was raised Protestant (Methodist to be specific), and they teach pretty much the same thing. If you ask God for something, and you don't get it, it may mean he has a different plan in store for you, so you must trust in him that he'll provide what you need, not necessarily what you want. The problem with Russ is that if you tell him "no", he immediately assumes that you're doing that out of spite, instead of not being able to promise something, or not being in a position to give him what he wants. Given his reaction, it's almost as if he wanted the Bishop to grab a "10" of his choosing and order her to marry him. He doesn't a wife for a companion, he wants a legal sex slave.Not only that, but his Bishop at one point had a talk with him about how if he didn't find a wife in this life that he would be able to find one in the afterlife. The Bishop was obviously trying to be kind and comforting to Russ, but Russ of course took it as the Bishop basically telling him that no woman will ever want to marry him, flipped his shit, and left the Church in a childish tantrum.
Everything Russhole does is for selfish and self-serving reason. You're quite right that his mentality is "If I do/say/buy/wear/give/etc. A, then I will get B or C that I want to happen WILL happen". He went on a mission, not as a selfless expression of faith and to serve God and his fellow man, but because he expected hot LDS girls to line up to marry him and because his parents wouldn't pay for his education if he didn't go. LDS girls grow up hearing how they need to marry a good, righteous man who is strong in faith and willing to serve the Lord by serving the Lord's children and sharing the Gospel. But Russ doesn't get that. He just saw it as a shortcut to a hot girl to have sex with. It's kind if like CWC with the high school reunion. "I went on the stupid mission, now give me my hot girlfriend! It was basically promised!"
Because Russhole is such a selfish, shitty person and his thought process is so fucked up, when his Bishop talked to him, Russ essentially saw it as a broken promise. God/the Church/the Bishop/life/whatever welched on a contract in Russ' mind. It doesn't matter that his Bishop never said Russ would never find a woman to marry and was just telling him that if it didn't happen in this life that it will happen in the next life, Russ heard: "No one is ever going to love you. You're an ugly, slack-mouthed loser. You're broken and don't deserve a woman who loves you." Since Russ wasn't being given what he wanted RIGHT NOW he no longer saw any reason to stay.
And I totally agree with you that Russhole likely never had strong faith. In the LDS faith you hear a lot about God's plan for us and to trust that our Heavenly Father will bless us for our faith and devotion. Trust in God and the plan, be a good person, and you will be blessed. Sometimes God's plan means that we need to wait for the things we want, but He always provides what we truly need. Russ never had the faith and patience to let God's plan work, and he is NOT a good person. If his demands aren't being met, if he isn't given what he wants RIGHT FUCKING NOW, then he does what all spoiled, selfish children do when they aren't given what they want: he kicks and screams and pitches a tantrum, then he storms off. Why should he waste his time by being a good person and faithfully obeying the Almighty when he's not getting everything his slimy, black little heart desires right this fucking second? Trust that the Lord has a plan for him and has his best interests at heart? Hell no! Throw a tantrum and storm off like a spoiled four-year-old brat!
And that doesn't even touch on what a shallow asshole he is and was demanding a HOT girl to marry, even back then. Not a cute girl. Average girls can keep on walking. Fatties need not apply, and heaven forbid it's a girl with Moebius or other deformity/disability. Russell Greer deserves only the best, hottest women, and don't you DARE tell him his expectations are unreasonable and unrealistic. He's got standards, damn it, and he's not going to settle for anything but the best! If you don't support him, if you tell him he should settle for some uggo or fatty? Well, you're just a hater or mentally ill troll who, for some random reason, just wants to see him unhappy and keep him from what he wants.