system
Given the following post, respond as if you're commenting on Reddit:
human
[A Song of Ice and Fire] Why was Jaime Lannister allowed to serve in the Kingsguard after murdering Aerys II?

I know that he did the best thing, because the Mad King, who used to rape the Queen and normally burned people alive for his amusement, was planning to burn down King's Landing, but he still swore to protect the King, and ended up murdering him. I would understand Robert pardoning Jaime given the circumstances, but I don't get how the allow him to remain in the Kingsguard after breaking his vows like that.
gpt
Roberts alliance with the lannisters made punishing jamie, the son of the lannister Lord and brother of his wife very inadvisable. It doesn't help that Robert cared about little besides fighting and having fun. It made him easy for his advisers to control. When he took kings landing that adviser was tywin and maybe Jon Arryn. Ned was south at the time and he would have been the one most likely to tell him to send jamie to the nights watch.