I think the point is that there is more to 'class' than money. If you're a single income family in a low cost part of the country where the working person is pulling in $100k working 40 hours a week in a stable and secure job, then you're definitely upper middle class.

If on the other hand you're a dual income family in one of the more expensive parts of the country and both of you work 60 hour weeks in a very insecure job market to clear a combined $100k then you're probably not upper middle class.