Soft masculine guys are those who have aged quite a bit and matured so much that they look like grandpas who are so done with life. I mean masculinity makes men be tough, confident and all around be more childish to endure so much punishment than women while still be able to continue living. Being soft masculine is like balancing being a bitch to being a man.
Firstly, guys can be open-minded but they aren't manly enough since you can't balance both due to the tough constraints on how guys tend to be raised. If you act nice, it means you are weak and girls would easily scam you, this being thought by our parents due to how guys tend to be raise to be more independent on women.
Secondly, most soft masculine guys are often been seen to be granpas and such, mainly because of how much mature and so done with life that they don't have to always act masculine all the time and be confident at the same time since They DONT care even if they get embarrassed or stuff since they only have limited time living. On the other hand, guys who are still young can't always act confident and even open-minded due to being afraid of taken advantage off while also confident in themselves, afraid of failure that would last a long time.
While women are free from being judge of being masculine or being gay, guys are often laugh if you act too nice or even feminine enough to be labeled yourself as gay. Guys are not only conditioned to be man, we are often judged to be presentable to not be judged as embarrassment as well. So its literally quite hard to be a soft masculine unless your man-child, dense af, or has a mental fortitude being built through the years of depression and such.