Thjazi abused Bolaire and that excuses everything Bolaire has ever done ever. He's Just A Little Guy who only torture-murdered people because he didn't know any better. Uwu.
THE BLEAK (wtf is wrong with you)
Bolaire is lying about Thjazi abusing him because Thjazi is just such a good guy - he would never do that. Freedom fighters never mistreat the people close to them. It isn't narratively satisfying to depict the hero who the DM has explicitly depicted as a Complex Man who, and I quote, 'robbed, killed, and abused people', as actually Complex. Anyway Bolaire is a nasty person so he deserved everything bad that ever happened to him :) In fact, it was WRONG and MEAN of him to kill the soldiers who enslaved him. No wonder Thjazi hated him so much!
Bolaire and Thjazi are each other's mirrors. Two sides of the same messy, hypocritical coin. And they would be so, so mad at anyone who points this out.