Inverted Triangle by itself can be a compliment because it represents broad shoulders and tight waistline, hard to acquire with working out; has nothing to do with legs AFAIK. Adding brawny before it insinuates that all he has is his body.
If it changes context for you it is the word ムキムキ muscular or brawny.
The speech box is ムキムキ逆三角形共にかまってる暇はない。
"I don't have time to waste on brawny inverted triangles."
I think is what I wrote I asked A couple people if I was missing some subtext... But not really.
I feel like it was said to confuse Ogaki, and it was super effective.
The type set/proof reading team has problems with swim team members... They add some flair to my lightly edited Translations.
The final product Rarely sees my notes. But they are just to help everyone get A better final product