I don't think it is useful to second-guess this specific case, Nate: We have one side of the story, and have no way to get the other side of the story, so it probably is best not to speculate either way.
What I think you can say, Nate, is that there are occasions when we guests have cornered CMs into truly impossible situations, where there is no possible response, on their part, that would not be readily interpretable as discourteous or otherwise inexpert. Unlike them, we guests are under no obligations to play fair. Without regard to any specific case, it cannot hurt to impress on folks that the CMs who help us are people too, and that we shouldn't be pushing their buttons or pushing them into a corner -- any more than we would want someone pushing our buttons or pushing us into a corner.
(And I know this has, in the past, included myself, having reviewed, in my mind, after-the-fact, some customer service situations I've been involved in. I now very deliberately consider this when talking with CMs -- with any CSRs for any company really -- and work very hard to ensure that I don't do that.)