Why All Of The Bother?

Pardon me for writing as guy, but I have read some things on here about acceptance of bisexual divorced moms. I am a son, age thirty, and for the last several years my mom has been having a bisexual friendship with a friend. Both are divorced, both have kids, and they are very good friends who have a good time being together and enjoying each other’s company as well as companionship.
I certainly have no problem with this. In fact, considering that my mom was married all those years to my dad, who was a rather abusive person, I honestly I can see why she would like to have a time out from men and the complications of male-female relationships, nd perhaps enjoy some female companionship. My mom works at home and has her own online business, which her friend, Jill, has also become involved with. And yes I know that, weather permitting, the two of them enjoying being at home nudists around the office and such. I think this sounds like fun and is great. My sister and my wife have no problem with any of this, either. What does my dad think? None of us have any idea. He has by choice disconnected himself completely. But that’s dad for you.
And yes, I have gone over to my mom’s house, and I have seen her and Jill happily in the buff. I find that amusing and certainly cooler and more fun.
So I do not understand why anyone would want to deliberately deny their moms some happiness and fun? Or is that just being too simple?