Quite honestly, very very very few current internet commentators seem to really grasp what JKR was pointing at with Snape and his background, and I think it’s partly because it’s so incredibly British in its depiction. Class exists in other cultures, but it really permeates British society in a manner that’s difficult to really explain to anyone outside of the UK.
Snape’s poverty is also of its era; the deprivation alluded to is difficult for anyone who grew up in the last 15 or so years to completely appreciate. That’s not to say that people can’t read up about it, but it’s not quite the same as having that first hand experience. There’s a specificity about it which means that if your experiences are of the Blair era onwards, and/or you grew up in a different social class, you possibly won’t quite grasp it - not least because, thankfully, society has improved a lot in many areas.
So much of what JK writes about Snape’s background relies on shared culture, as opposed to being categorically spelled out within the text. Harry’s neglect and abuse is explicitly written; Snape’s is alluded to - and the disparity in how she depicts the two means that many miss what’s really being suggested when it comes to Snape.
Personally, I find her handling of Snape’s background incredibly deft. That shared culture means that many people read the passage where Tobias is shouting at Eileen, and those people nod their heads and say, “I know exactly what went on in that house.”
Snape’s background is a depiction of endemic unending poverty, domestic unrest (and implied violence), and abject neglect. It’s also why so many readers leap to the conclusion that Tobias is violent towards Eileen and towards Severus. That presumption seems to leave so many on the internet baffled at such certainty when it’s not actually written in black and white - but what they’re missing is that JK has used a social shorthand that everyone ‘in’ on the meaning understands.
Furthermore, it’s rarely discussed, but there’s a very good reason why Lily responds to Snape’s Mudblood insult by highlighting his poverty and neglect. Snape’s ‘greying’ pants aren’t about him being unclean - white clothes ‘grey’ when they’re old, and that’s what Lily’s remarking upon. (After all, it seems unlikely that the kids are responsible for their own washing - you would’ve thought Harry would’ve whined about washing his socks and pants, as opposed to his magical homework. Do we really think Snape wasn’t washing his clothes, or rather that his clothing was substandard to begin with?)
Notably, Snape highlighted her otherness in the magical world, and she threw his otherness in society right back at him.
And that’s just looking at his comparison with Lily - she was loved by her parents, and grew up in a middle class home. The only thing Snape has is his knowledge of magic…and that’s the one aspect he can bring to their friendship which impresses Lily.
James, on the other hand, has the full house - he grew up in a wealthy home, with parents who adored him, in a magical society. The situation between James and Severus could not be more unequal - and it’s got nothing to do with dark magic.
It’s also an analogy for the grammar school system - which again, is lost on a lot of people, because it’s very of its time. Snape is the kid who comes from the sink estate who passed the exams against all odds - and when he gets to the school, where he’s earned his place, he sticks out like a sore thumb. He has the talent to be at Hogwarts, but not the social background.
On the flipside, James is the depiction of a kid who was always going to get to grammar school, who belongs at the grammar school…he also has the talent, but he has everything else as well - and he can’t fathom why someone from Snape’s background is sitting next to him.
That’s not a criticism of James - it’s an understanding of where his character comes from, and why he reacts so violently towards Snape, but he doesn’t react in a similar way to Sirius. This doesn’t excuse his dislike, but it goes some way to explain it. It shows why other characters like him so much - he’s fun, and clever, and nicely dressed, and confident, and sporty, and talented…but he can’t get past his outright dislike of Snape, which grows over the years and encompasses other issues (such as being jealous of his friendship with Lily).
There is a very important parallel that James and Sirius don’t accept Severus because Severus’ background makes him other - just as the Death Eaters and their ilk don’t accept Lily because Lily’s bloodline makes her other.
