The guys, except for Obanai and Gyomei always try to impress you. So they decided to have their shirts off randomly to show off their muscles.

Tengen: “They’ll obviously fall for me! I’m more muscular and taller than all of you!”

Sanemi: “Tch please…you’re too cocky for them.”

Giyuu: “Maybe they prefer the quiet ones…”

Rengoku: “I bet they’re into flame guys like me!”

Obanai facepalms and Gyomei just stands next to him, wondering why they’re arguing(he’s blind if you already don’t know)