Visibility hidden isn't inherited. This means that if a child is set to visible, it will be shown.
Unity, huh, how?
Visibility.Visible and instead set to StyleKeyword.Null.visibile property, instead create an extension method that uses corrected behaviour./// <summary>
/// Styles an element to stop it from rendering.
/// </summary>
/// <param name="element">The targeted element.</param>
/// <param name="isHidden"><paramref name="element"/> is hidden if true.</param>
/// <remarks>Unlike <see cref="VisualElement.visible"/>, because <see cref="Visibility.Visible"/> <i>forces</i> visibility (even as a child of a hidden element)
/// this method sets the visibility to <see cref="StyleKeyword.Null"/>.</remarks>
public static void SetHidden(this VisualElement element, bool isHidden) => element.style.visibility = isHidden ? Visibility.Hidden : StyleKeyword.Null;Avoid the visibile value; instead try to invert the logic and only apply hidden.
Note that USS variables can help solve tricky problems and avoid complex selectors.