Iowa Code 723A
(1) "Brandishing a dangerous weapon" means the display or exhibition of a dangerous weapon, with the intent to use, intimidate,
or threaten another person without justification, or the actual use of the dangerous weapon in a manner which is intended to or does cause serious injury or death without justification.
(2) "Dangerous weapon" means either of the following:
(a) An instrument or device designed primarily for use in inflicting death or injury upon a human being or animal, and that is
capable of inflicting death upon a human being when used in the manner for which it was designed.
(b) An instrument or device of any sort whatsoever that is actually used in a manner that indicates the defendant intends to
inflict death or serious injury upon another person without justification, and that, when so used, is capable of inflicting death or serious injury upon a human being.
Now, ask yourself it that fits the description you posted, or is someone reading more into the law than the law describes?
Brandishing is a crime, and people get arrested for crimes. If getting yelled at is all that happens when someone commits a ""crime"" then it's quite likely it wasn't a crime to begin with.