Let it go bruh. Its over. Its canon.
http://www.westeros.org/Citadel/SSM/Entry/Asshai.com_Forum_Chat
Kingsquard a probably gassed people up on Rhaegar. I bet all the dude Rhaegar faced in that one tourney he won jobbed.
Robert and Stannis were still young, and as far as I remember - Robert didn't really start being an a$$hole to Stannis until after he won the crown.
To be honest, Stannis has every reason to be pissed off. Stannis held off the Tyrells at Storm's End, won Dragonstone for Robert and smashed the Greyjoy Rebellion. Without Stannis, Robert really ain't shyt. What does Robert do to reward his brother? bytch ass Robert gives sword swallower Renly, who didn't do shyt, Storm's End. He gave Stannis ass Dragonstone. bytch ass Robert blamed Stannis for Viserys and Dany getting away too. Stannis was the one who figured out Cersei's kids weren't actually Robert's kids. He knew he couldn't go to Robert because Robert wouldn't believe him, so he went to Jon Arryn instead.
Renly was the biggest a$$hole out of the three brothers. He had absolutely no claim to the throne over Stannis. This entitled mufukka tried to leapfrog Stannis for no absolute reason. If Renly just listened to Ned & later Catelyn, he would've probably been Stannis's hand and eventually king since Stannis didn't have a male heir. But instead Renly decided to be a dikkhead and got sonned for it
Things were already sour between Robert and Stannis. I take it Robert never really got to chill with Stannis because he was always It may have been meant as a slight but placing him in Dragonstone was probably also a good move since that area had Targaryen loyalists that needed sorting out and it also acknowledged him as succcessor (when you look at how Targs did it).
Also Renly listening to Catelyn would have been bad for him because no way in hell was Stannis gonna make Renly King's Hand over Davos. shyt would have just deaded his campaign and only thing he have kept was maybe Lord of Storm's End. Renly was an entitled a$$hole fool but he had a big ass army and a net of notable figures to protect him which is why Stannis had to resort to voodoo to take him out. With the circle Renly had he would have made a great peace time King. Remember Sir Cortnay Penrose? The man ETHERED the fukk out of Stannis when he tried to take Storm's End. Who made him castellan?