There are plenty of articles online about Graham Platner to quote but you instead linked a 30 minute long video without a timestamp. Please link me the timestamp.
I will give you a hint: You are currently stuck in a delusional world view in which you are rationalizing the beliefs of Graham Platner to be what you want to believe.
Graham Platner never said he regretted his time as a child murdering terrorist. He only regrets how much taxpayer money was wasted because he could have killed brown people so much more efficiently.
You are doing the exact same thing the MAGA crowd is doing for Donald Trump. Projecting your own desires on your favorite politician who is promising to fix your own economic woes and rationalizing all their flaws away for it.
Now go find that timestamp or quote you are so certain exists and prove me wrong.