Interesting topic.
The topic Male sexuality, in ever which way is a slippery slope. It doesn't end with the body. All forms of " man care" are always some kinda sus. For example fashion, facial care ect. It seems like a thin line between caring too much and don't care enough about yourself as a man.
I read here I believe a great hypothesis. Before Arnold and Stallone bodybuilding wasn't a big thing.
This is Luke Skywalker in his prime. Back then a absolute sex symbol. Nowedays his physique is laughable.
With the rise of bodybuilders as role models came also the rise of everything that we see today. So our fathers could look like Luke ( a physique you'll get when you work manual labor) ,and be deemed as sexy. A way more natural looking body than we see now which didn't take any extra effort. Nowadays a man must work fulltime, and on top of that work out to at least be average. So our fathers (unconsciously) thaught us that a LUke physique is just fine. Its similar to how our fathers thaught us a good woman stays in the kitchen, and within their lifetimes this narrative completely changed.
If you look at modern tv shows as ex on the beach you'll see empty shell dudes but with a good body. Putting too much effort into your appearance seems sus, but the pressure from "society " forces a man to follow the program. If a individual man decides it's not important he'll need to be damn confident , and be a natural with women to dgaf about the picture modern society wants to see. Hence the rise of incels.
Funny story; I have a cousin how always was a natural with women. One day ( we were young like 14-ish) my cousin said he sometimes would put on little bit of eyeliner to make his eyes pop. Sus AF but he was so confident he could get away with it .