This has been done before, but it is women fighting women to say that those who cannot access facilities without their children in tow should fuck off. There is a mindset among some people that mothers in the role of mother should be all that society socialises women to be (quiet, apologetic, take up as little space as possible) and take their place firmly at the bottom of all possible piles and the end of all possible lines.
I had a conversation with a woman who felt her want to walk about the changing room naked to apply moisturizer in front of the mirror in the communal area, then return to the only cubicle which she had her clothes in to continue to dress, trumped my need to get myself and my children (then 6, 4, and 1 - the eldest a girl, then two preschool boys) dry and dressed.
She didn't need the cubicle and the whole changing room, but felt I should change in the disabled toilets with my 3 kids because she wanted to use the cubicle and walk around the communal area without the boys potentially seeing her.
I rolled my eyes at her, her wants in that case did not trump mine.
Biology and socialisation and years of patriarchy mean women often have sole charge of very small children. If children are allowed in the facility, then mother's have to be allowed to take their very small children into changing rooms and toilets.
When the children are capable of using facilities alone it is a different issue, but taking a very small child of either sex with you isn't about protecting them from adults of their own sex, but about the fact that while children are under about 5 or 6 and unable to navigate facilities alone, their mothers would be largely trapped at home in many cases otherwise.