Earlier quoted context omitted.
You wouldn't need an extravagant income to do something like that. I just did a quick check and it costs less than $150 to overnight an 8lb package from NY to SF with 8am delivery. So the markup over just buying the meal at the restaurant is going to be less than $300 once you add refrigerated packaging and pay somebody to order it, pick it up, package it, and ship it. That's pricey if you're doing it every week, but…
Really - a $300 birthday gift to your friend? According to this website[1], the median American family has a combined income of 81k and spends about 1k of that on gifts. That's for the whole household, so more like $500/year for your friends. You're probably not going to blow half of that on one friend's birthday dinner. Of course there are plenty of people for who this is reasonable, but please don't be so ignorant…
And some people are a bit more generous than that. Or only have 1-2 friends that they go "all out" for. Small $20-40 gifts for a few friends/coworkers and 1-2 $200-300 gifts for the close friends lines up with your estimate just fine. Especially since they said could afford to and not will do so.
I'm middle class and spent three times the average you cited because I budgeted it accordingly for the last year. This year was atypical, but was very much possible.
You don't need to be upper middle class to afford a one off large purchase. Maybe if you're struggling in the lower ends of the working class - it could be difficult. I don't see where you're finding fault with their statement... if anything you're supporting it.