She is "acting like one". She got married, she built a home, she had a child. She has put rules in place to protect that child, and when people repeatedly ignored those rules and put her child at risk, she put her foot down and stopped allowing them access to her child to protect them.
That's is both acting like a grown woman and being a bloody good mother.
What are you on about difference of opinion, just getting on? Ignoring rules someone set to protect their child and doing things they told you not to anyway isn't a difference of opinion, it's disrespectful a d no one has the right to do that whoever they are. No one gets to tell me that they would do this things differently to me then proceed to do whatever they want to my daughter. Hell no.
You're insistence on posting nasty judgements about a woman you haven't met and no nothing about and deriding her calling her a child etc. is gross. And cutting someone off because you don't like the way they treat you or children is not "having a tantrum" it's exercising your freedom not to waste your life on people who upset you. Everybody is entitled to not want to spend time with or talk to people who are upsetting them.
Sorry but if you told people you'd didn't want them to do a certain thing to your child, then they kept doing it anyway and you just saw it as a difference of opinion and let them carry on, they ARE walking all over you.