I think it depends what not particularly rich means. I think people with skilled technical jobs: builder, scaffolder, plumber - can do very well because their talents are forever in demand. They often continue to live where they went to school and therefore often get childcare help from their parents. If they are not paying for private schools, then they probably have a lot of disposable income and identify themselves as successful. If self-employed, they probably find if possible to offset expenses against tax, and therefore flourish in their trade or calling.
On to that basis is the fact that people who come from less privilege do actually know and have grown up with acquaintances who were not as lucky or skilled at managing money and opportunities. I find that the petit bourgeois of successful tradespeople is a group which expects individuals to make sensible choices, all the time. Members can sometimes be very much less than sympathetic to those who have chosen the wrong bloke or made a bad mistake financially. In my experience talking to this group.
However, those socialists who are upper middle class tend to explain poverty, and also socially unacceptable behaviours with broad brush theoretical explanations about economic forces and entrenched privilege - and they don't know many people who have grown up deprived so don't feel irritated by friends who keep making poor decisions and, as the Tory voting working class would see it, causing their own problems by their irresponsible actions.
I've always found this, anyway, from people I know. People from ordinary backgrounds who are now earning well, know the nitty gritty of their best friend's disaster and judge them more harshly than some more privileged folk would do.
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