Such men look anorexic and.. not so manly lol. Also, having barely any fat is not good for your body when you're ill and you don't feel like eating or you can't keep down food. In my opinion, model skinny is unhealthy and shouldn't be viewed as a target to work towards and idolise.
With the pictures you put up I don't mind all of them. Model skinny isn't always unhealthy, there are many people who are naturally skinny. When I see a skinny person I never think "they probably don't eat anything at all", not true at all, seen many skinny people eat like a pig. Also seen many healthy looking people eat a whole lot of junk food so they aren't necessarily healthier than everyone else just because they look it.
I like a men with a good posture and a fit body. I never found attractive an anorexic looking guy or a body "made out of steroids"... just... NO! You have to train because is healthy and because it makes you feel good and look good. Most models are full of steroids... not nice.
Some girls are more into muscles while others prefer the skinnier guys. Some of them look unhealthy to me but I have seen others who look healthy and attractive while still being on the skinny side. I prefer fit guys though.
It's only for clothes to fit. No guys generally like adequate titties and ass
I don't find it attractive per se, but if I got to know the guy and that's just how his body is (very high metabolism) then I can't judge. Same if he was chubby. If I liked him, I'd date him either way.