There's always room for more answers, but there have been a few answers related to Robert E. Lee on this subreddit that will give you more information on what his actions and beliefs actually were:

• /u/TRB1783 on the establishment of the myth of Robert E. Lee during Reconstruction

• /u/Rittermeister on Was Confederate General Robert E. Lee actually fighting for Virginia and state's rights, or was his allegiance racially charged?

• /u/dandan_noodles on Robert E. Lee is lauded as a military genius of his time, but what were his real victories? Most of his 'decisive victories' seemed to have been more of utter failures and poor coordination by Union leadership rather than ingenious use of strategy by confederate leadership.