Um? No one said men can't be feminine. The question you should be asking, is why do yaoi authors so often feel the need to make the one getting dicked down have a feminine body? Men do not have hourglass figures and chests/nipples that look like female breasts. Idk how many gay men you know, let alone men in general, but I know a lot, and I've never seen a slim thick body on even the most fem bottom of a man. The, "other body type," you're talking about is almost impossible for men, even with exercise. The bottom and tops chests are both big, the tops looks like a chest someone who goes to the gym would get. The bottoms chest is squishy fat, but that makes no sense for his weight and anatomy. His stomach is flat and his hips and ass are huge.
Big boobs, flat stomach, wide hips, big ass. What are those? Oh yeah, female beauty standards. Not what gay men really prioritize. Given they're attracted to men. Not women.
It's time to start asking yourself why you want to see a man who is built like a woman, rather than a fem gay man who still has a realistic body type.
There's the saying, 'bl proportions' that's literally based around how bottoms will look extremely small and feminine and the tops look huge. There are SO many webtoons that have fem bottoms with slim waists big butts and too big of chests for their size.
Why is that? Uh, again, bc female beauty standards are being pushed onto bottoms causing bottoms to look more anatomically feminine. How and why is that a good thing? The submissive one isn't just pretty, but also has to be built like that. Oh okay, that's not weird.

What's with the bottoms overly feminine body? does the artist know its okay for bottoms to look like men and not women with a slightly thicker waist and dick? Dude is looking like some femboy 2020 tumblr oc