I'm reliably informed by a contemporary at Westminster Grammar that he "wasn't that posh" until later.
I always find it irritating that politicians of all stripes who have gone out of their way to cultivate a particularly niche image are lazily described by the commenteriat as more "authentic" than those are quite happy to dress and speak like regular politicians and demonstrate their authenticity (or lack thereof) with the actual positions they hold
I mean, he did go to Eton and then Oxford, he is married to Helena Anne Beatrix Wentworth Fitzwilliam de Chair, , his father was Lord Rees-Mogg, he is absurdly wealthy, etc. etc.
So, despite what random commenters on a tech forum (or their friends) might have to say, I think the simplest explanation is that he just is posh.
Obviously, he plays into his image (He doesn't exactly hide this fact). But that doesn't mean his image is false.
Politics is full of people with well connected families and money who managed to attend Eton without coming to resemble the Rees Mogg "Honourable Member for the Eighteenth Century" novelty act.
Nobody is pretending he was born poor, we're just noting that that person who had the same level of privileged background as dozens of other politicians probably isn't more "authentic" than them because they're not regarded as caricatures...
Rees-Mogg's character isn't an act so to speak, but it belies his true origins. He's not upper class - he's upper-middle, if we're being fairly strict in our definitions of British class. Being the son of a life peer isn't the same as being the son of a hereditary peer in terms of its conferral of social class. Rees-Mogg's father, William, was born middle class and was elevated to a life peer for his journalistic career, rather than being a titled hereditary peer.
Now for some useless internet anecdotes.
I was actually at Oxford with Jacob's nephew. Very humble chap, very likeable, and very liberal in his conservatism. Was always quite reluctant to spill the beans on Jacob though, which is fair enough.
Also interestingly is the continued existence of people like Hannah in the article. My tutor, a professor at Christ Church (informally seen as one of the most 'aristocratic' colleges), was 'busted' for running a secret dining society populated by public schoolboys, a number of whom would be described as being upper class. This is despite him coming from a relatively modest background up in Hull, and never entirely managed to shirk his regional accent. He didn't even read for his undergraduate degree at Oxford, heaven forbid! (Great guy though). Now it all makes sense as to why he was so inquisitive about my schooling and family background during our first meeting.
My cousin, who was also at Christ Church, knew a couple of the Bullingdon chaps. Heckling members of the public in the King's Arms because they didn't live in a castle was one unbecoming episode, as was another member turning up to a college party in a KKK outfit. From my understanding, traditionally upper class societies like the Bullingdon are strongly falling out of fashion and becoming much more underground, because of the toxicity surrounding them. While I was there, the Bullingdon club were caught assembling on their usual steps in Canterbury Quad in their tails, to take their annual photograph. They were promptly kicked out of college and told that they couldn't assemble in Christ Church again. As a result of this toxicity, they've had to expand their social reach to more non-traditional gents, in order to keep the club alive. Now more than ever, simply being from a wealthy family, rather than an aristocratic one, seems to qualify.
It's also right there in your own comment that he "plays up to it", which is pretty much the definition of an act. Many people manage to be related to life peers and even attend Eton without appearing to be auditioning for a role in a costume drama about eighteenth century aristocrats.
I always find it irritating that politicians of all stripes who have gone out of their way to cultivate a particularly niche image are lazily described by the commenteriat as more "authentic" than those are quite happy to dress and speak like regular politicians and demonstrate their authenticity (or lack thereof) with the actual positions they hold