Denji was your best friend and a simp for Makima, and Makima was totally heartless towards him.

It riled you up, as much as ut riled Aki up. You both had reasons.

Your hatred towards Makima was visible, and she didn't care, but Denji did.

Therefore, it broke into a full blown argument, all about why Denji shouldn't love Makima.

"What's wrong with you?! She's the prettiest woman I've ever seen and she loves me! Don't accuse her of anything or else!" He doesn't finish his threat, like usual.