It always baffles me how even in the modern football culture, a lot of fans still feel that players should be loyal or 'owe' the club in some way. In Paddy's case, he was banned but still under contract so the club were obligated to keep him, unless of course they sacked him which would probably have meant paying up his contract. Ched for example, was out of contract so the club simply released him at the end of that season (why wouldn't they). Shortly after the end of the ban, the club accepted a substantial offer from QPR for Paddy and he and more importantly, the club, accepted - so I don't see the problem. He's not a 'blade' as far as I know, he's from Halifax so it's not like he was playing for the club he supported as a kid. We don't know what was going on behind the scenes at the time.
Looking at the cases of Currie and Deane. Currie still claims he never wanted to leave but was literally driven to Leeds by then General Manager, John Harris and told to sign for them as the club needed the money. Although Deane admitted he supported Leeds as a boy, claims he didn't actually ask to leave and would have been happy to stay. We all know that it was Brealey who sold him without Bassett's consent and he could have ended up at Wednesday as they had offered £3.2m and Deane claims, "he couldn't do that to the fans".
A different case is Dane Whitehouse. Apparently Birmingham made an offer that was accepted by the club, but Dane went to see Spackman to check he would be in the managers plans. When he was reassured he would be, he rejected the move and presumably the club didn't push it. However Dane is a boyhood Blades fan so has much more affinity with the club than the others.
Thankfully, as far as I can recall, we haven't had players like Berahino who famously engineered a move himself and proper spat his dummy out about it or Van Hooijdonk at Forest who went on strike because the club wouldn't let him go.
Just check if the club 'looked after' Joe Shaw after he'd played around 650 games for the club and 20 years service.
It seems to me that the only real loyalty is that of the fans who have no choice but to slavishly follow their club through thick and thin.