DaRealness
I think very deeply
There is a lot of variables that come in mind though.
First, if a dude is nice because that's who he is then he should remain nice. There is a difference between being a nice person and being someone who can't stand up for themselves or believes in boundaries and morals. A dude is losing if he changes how he acts for a female. For example, he believes he has to be an a$$hole to get a female when he's probably a good dude at heart. It's straight-up losing for a man to lower himself to that. Now if he's pretending to be a nice dude just to get laid it's a different type of story. Dudes will snap on their own grandmothers or best friend of ten years for leaving the lights on in the bathroom but will let a girl they just met break all the rules just so he can smash. That's the corny shyt right there.
As for some mothers punking and softening their sons, it's somewhat true but not all of the time. I mean shout out to moms because they're awesome but not all of them are innocent as the public tries to display them as. I grew up with a few dudes who's mothers were straight-up a$$holes that punked their sons in public for absolutely no reason. And of course, I knew what brehs was going through at home behind closed doors. The common factor was always the same for these moms though. They either hated the dad or he wasn't present at all so in some weird way they take it out on the children.
Another reason why moms soft dudes up at a young age is because they love them. There is never any ill-intent when it comes to this variable. They are the codependents in their sons' lives as they give advice on dealing with women. But that's when the father needs to be present more than ever. A mother's love is unconditional and a child always needs that father to hit them with a dose of reality when need be.
Everything can be solved if a breh has a strong male role model to teach him. This could be their fathers, step-fathers, uncles, older cousins and so on. And if they don't have dope male figures to follow then they should try to find a source through media. I listen to dudes like Dante Nero, Joe Rogan, Charlagmane Tha God, Lord Jamar, T.K. Kirkland, etc. A lot of them dabble in the same medium but all dudes with different personalities that have one thing in common. They are up there in age.
Respect your elders is a saying for a reason. A lot of them have wisdom that the youth could use. But in our culture, especially hip-hop, we look at you as trash once you hit a certain age. This leaves young men being softened up by their moms and their role models are 20-year-olds who never make it past 25. The result is brehs nowadays have women issues, discipline issues, common sense issues, morality issues, self-esteem issues, and a shyt ton of other things.
This is my point and most people don't even speak on this. I've seen it countless times over the years. They take all that hate out on their sons because they chose to mess with a man they knew was no good in the first place.
It may not always be a deliberate sabotage, but other times its subconscious. A lot of these women know they ain't shyt, so deep down they feel as if they warn their sons about the no good women out there then they are actually telling on themselves. Men are way more inclined to warn their daughters about men than women are to warn their sons. It's always the father (if he is around) who warns their sons. Like you said, a male role model is vital.
As for being a genuinely nice person, yes by all means be that. However the reality is, life is harsh and sometimes you will have to tweak certain things about yourself in order to adapt and survive your environment.