If someone doesn’t agree with you does it mean they lack understanding

I’ll use some personal examples:

My mom and I were having a discussion about how she was going to buy all pink clothes and tutus for my daughter so i asked why? She replies “so people know she’s a girl.” I say “ok? I probably won’t dress her in that.” She says “ so you want her to look like a man.” This is the first wtf of me not agreeing with her on the first part. I said I wear pants does that make me a man? She goes on to list the “appropriate” colors that are okay for a girl to wear.

Next we have the whole ear piercing debate. She says my daughter will be mad at me that I don’t get her ears pierced as a baby. She says babies will not pull on them and I disagreed with that. Secondly I told her my fiancé and I agreed to wait until she wants them. She told me she got my ears pierced because she wanted me to have them not because I asked.

Last part of the discussion still about ear piercing but for men. She said she will never allow my brothers to get both ears pierced. I asked why? She says it’s an identity issue. I disagreed because it’s just an ear piercing and means nothing. I have heard things said about men getting their ears pierced but I don’t think it’s true as that’s why they do it.

So she said if I don’t agree with her then I lack understanding because I disagree with her.

My question is when you’re debating or even just having a conversation with someone, if you or the person don’t agree with each other does it mean one or both of you lacks understanding?