I mean, if you view manliness that way go right ahead.
I see it as being whole enough in your manliness to let your guard down. But hey, glass half-empty may be the way forward for you
So, in other words, manliness is to behave in ways contrary to the masculine nature--is that it? Toughness, hardness, strength, stoicism--these are naturally masculine traits. Vulnerability is not; it's a feminine trait. That is why, when things go pear-shaped, men are expected to fix things; when someone's being attacked, people don't look to women to go save that person--they look to a man. The world is ugly and hard--men are the ones expected to be able to tough it out, and a man who "lets his guard down" in it is a man who won't survive in it long; at the very least, he can be expected to take some serious losses--and to cover all bases, no woman actually wants a man who behaves like a woman at the end of the day.
What you said is very much like a postmodern excerpt from the old
open-mindedness playbook: "Oh, you won't wear pink? You must not be very
secure in your masculinity~" Over time, it led to things like this: "Oh, you mind other men hanging around your girlfriend/wife? You're so
insecure~!" I'm sure I'm forgetting at least one example of men being called "insecure" for not engaging in clearly homosexual behavior.
AnimeCruizer isn't wrong--those guys ARE acting effeminately, and it's been increasing in frequency over time; what saves the manga is that--the corruption aside--the story is generally wholesome, and Dariel's squarely outside of that effeminacy; what helps a lot is that his wife is unmistakably feminine and beautiful--a solid and logical choice for any good man worth his salt--and he has started a family with her. The story hasn't gone downhill because of the homosexual subtext (even if it's an ugly and growing flaw on an otherwise lovely painting), but you have to call a spade a spade.