It's funny if 'middle class' is being taken as an insult, because more and more British people like to claim they are middle class when asked in surveys.
I was brought up in the middle class and so (unless I was filled with guilt and self-loathing - both sometimes identified with the MC!) I won't say it's an insult.
Actually (classic middle class sentence starter) I think there are good things about the MCs.
Upsides
* They value learning and culture and make a point of supporting both.
* Middles often yearn for things to be better and want to build a better society.
* They can be very funny - some of our best comedians are of the middling sort. I love people like David Mitchell, Miles Jupp, Ian Hislop and Tom Hollander, all solid MC figures with huge humour quotients.
* Middle class people often do very socially useful things, like being doctors, teachers, university academics, theatre producers and tax accountants.
* They spread good taste and common decency.
Downsides
* Can be reserved, stuffy and cool.
* Have a tendency to be hypocritical, especially about the morals of the other classes.
* Make a fuss about things that don't matter (designer food, the right sort of wallpaper, what's fashionable to wear at Crufts) and ignore things that do matter. (Poverty, oppression of low paid workers who clean their homes, wash their hair, empty their bins.)
* Confused as to who they are. Many working class people wrongly claim to be middle class. So do some upper class/very wealthy people. Some middle class people 'move up' and forget how it was to be in the humble middle.
* Arrogant about their position and yet whingy about it as well. Quite a few solid middles are very well off and they act superior about that, but they still moan about all the iniquities of their situations.
* Tend to vote Tory a lot. Annoyingly. Although a segment of the middles that used to vote Tory has switched to LibDem and Labour.