Is there really anything wrong with letting kids use different words for genitalia?

My oldest knows the proper anatomical words for men and women, but she chooses to use other words she likes. The penis is “weiner” like a lot of other kids call it, and the vagina is “tootoo”... don’t ask me why, I don’t know, LOL. She has a younger sister and they talk a lot, so I’m sure these words have come up in their conversations.

Anyhow, my 4 year old said something about boys having weiners and a lady blasted me for not teaching my children the proper words.

Why does it matter what they call it? It’s not harming anyone, and at this age it’s just funny. I don’t feel the need to tell her “No honey, we don’t call it that.” It irritated me that the lady felt she had the right to condemn me because my little girl didn’t say “penis”.