Why are so many young men choosing to remain bachelor's and seem bitter at women and even mock men who marry?

I am a 35 year old Professional male attorney.I am happy in life,love my job and fiancee. I am getting married in December. It seems that a lot of my friends from college and at work who range in age from 25-45 are refusing to get married and seem bitter at women. On fellow coworker who is an Attorney as well stated to me that if I get divorced I will lose half my money and custody of children(I want kids). Many of my friends, who are considered handsome guys with money have absolutely stated they will not marry wahtsoever and some have given up on women completely. My friend who I will call "Jeff" is advising me not to get married that most marriages end in divorce.Jeff has been hurt by women in the past(His last girlfriend of 5 yrs left him for another guy).Jeff claims he was a "nice guy" and his ex girlfriend left him for a "jerk" who treat her badly.I told Jeff that not all women are like that and a good marriage can be a beautiful thing.It seems like these guys just want to remain bachelors and some of them I think really hate women cause they have been hurt. I feel like as a man getting married a target of ridicule by other men.I rarely bring my fiancee around these guys inasmuch as she feels a hostility from them. It really doesn't matter what these men think of me and I am not sure I even want to be friends with them anymore. My only concern is the future for my kids(I do want kids). If too many men are bitter and choose to remain unmarried, there will be a drastic population shift in declining childbirth rates.Plus,if I am blessed to have a healthy child who is a female she will have little available men to date in the future which is a damn shame. There are a lot of good women out there who would love to marry(My fiancee's best friend is dating a guy for 5 yrs and he has not even proposed to her) My friend "Jeff" .is even involved in a movement called "men going their own way"(MGTOW) part of this so called Mens Rights movement (similar to feminism for women. I went on the website "Happy Bachelors" and it appeared to me just a bunch of successful bachelor men who are bitter at women, and actually encouraging men to "Boycott Marriage".There was one gentlemen on one male blog who actually allegedly said he "he has now become homosexual" because of his hurt in the past by women. This is absolutely ridiculous and a damn shame for my future daughter(if I have a girl) and many young nice pretty unmarried woman looking for husbands.There will be a severe shortage of eligible men from what I sadly see amongst many men today