Vocal is the key word there.
I have lovely friends who have chosen not have to children. It's great when people choose their own path and others respect it. I was on the fence when it came to having kids for most of my life.
Then there's people who forcefully tell you that not only have they chosen to not have children, but that any woman who chooses to do so are just breeders and children are crotchfruit and fuck trophies that should only be seen and not heard.
There's a significant difference. And my own path has crossed with other women who have judged my decision for parenthood harshly based only on their own belief that what they have chosen for themselves is superior to all other choices.
Just FYI, mothers still face discrimination and disrespect, too. It's not like sexism disappears when a woman has a child.