after David suggested all of them reveal their secrets a lot of things happened, Arturo threaten Eden because of that, Nico almost killed ace over his secret, and arei having a break down due to revealing her secret, he was suspected to be the killer of arei, but they weren't sure after realizing that David is a manipulator, they cornered him for that

David:... Ah so sorry, I was distracted thinking about the last trial, how min was accused of murder, yet she kept fighting, arguing yelling even when no one believed her, only made her guiltier... Looking at her, back then I thought... he paused

David:how utterly pathetic she was, she should have realized how she was wasting her energy on that sad performance, the only thing she gained was gathering pity, back then... I thought to myself, if I were in the same situation, I would know when to give up, that way, I can keep my pride, with that in mind I guess I should stick to my words and give up.

Teruko:... David?

David took off his star hair clip

David:so then... he moves his hands upwards to his face revealing his true colors behind that well-mannared facade, his light eyes turned to grey, as he has eyebags beneath his eyes I'm guilty as charged, I'm a lying, manipulative, scumbaggy bastard, is that all you wanted to hear?

Hu jing:... D... David?

J Rosales:woah! Is it just me, or did he just completely change his demeanor?

Eden:wait! David calm down-

David:hold on, I'm not finished, didn't your parents teach you any manners ? Or are you all just ducking stupid to know how rude it is to interrupt someone's speech?
You were right, I'm a good for nothing liar, but I call those lies motivational speeches and everyone eats it up, people can always change... Hah, what complete bullshit, no one changes.

he started insulting ace in a truthful way

Ace:.. Now I dislike you bastard...

after all that "blah blah blah" speeches he made, you already knew about this because of his body language, you already know when you met him