Whenever I bring up the fact, that Severus is a victim of domestic violence at home, which basically fueled his vulnerability and reasonings of him being groomed into a death eater (since DEs work like a cult, they target the vulnerable), and people bring up Sirius running away at 16 from an abusive household, I WANNA PUNCH THEM.
It takes little to no amount of thinking, to realize that they have completely different circumstances. 1st off, Sirius was NEVER EVER abused before, there's no factual proof of this; The closest thing we've got, was Walburga being strict and favoring Reg over Sirius.
2nd, unlike Severus, Sirius had a shit ton of support. A key detail to this, is that Sirius was a GRYFFINDOR, meanwhile Severus was a HALF-BLOOD SLYTHERIN, sorted into a house full of pure blood supremacists DURING VOLDEMORTS RAISE, THE WORST TIME POSSIBLE. Sirius had the Marauders and the Potter's, Severus had no one. Even if he did have Lily by his 6th year, him and Lily lived in the SAME TOWN. He'd be found by the police or the Snape's under an hour. He'd have nowhere to go
3rd, Severus, unlike Regulus or any other DE, was GROOMED INTO JOINING. It's canon, that Severus never joined because of beliefs, but for the sense of belonging, as a SEVENTEEN YEAR OLD WIZARD, a teenager, that was mistreated by the light; Not only did the light side reject Severus, but it also literally bullied and tortured him; When you're being mistreated by EVERYONE from the 'good side', does it really seem like the 'good side' to you? No. Therefore, Severus chose the dark side, because that side treated him better than the light side ever did.
It's also important to emphasize, that the DE's function like every single cult. They prey on the vulnerable, such as Snape. Not only was he the perfect grooming victim, but also the perfect propaganda tool. Little to no Slytherins interacted with muggles, so who's to say they'd be able to differentiate propaganda and the actual truth? Especially since Severus was literally under an abusive muggle? The dark side saw Severus' vulnerability, as a traumatized, malnourished half-blood and took advantage of it, promising Severus privilege, power, respect, all the things that Severus craved!
He's craving for power and respect was legit what got him into SLYTHERIN (as his craving for power n respect could be seen as ambition, a literal SLYTHERIN trait), ofc he'd believe them and join the side that promised that?? Why are we surprised that a traumatized 17 y/o joined the side that promised him SAFETY?? ESPECIALLY SINCE HE WAS TORMENTED BY THE OPPOSITE ONE? HELLO??
And before all of y'all r gonna call me a nazi.. The DE's r not a nazi. Racist? Yes. Nazi? Fuck no 😭 And I'm not justifying Severus joining the DE's either. I'm simply explaining the reasoning why he joined and WHY it was realistic for him to join, hope this helps, xx
Edit 1: Y'all nvm, Sirius was abused (at least psychologically) by Walburga. I reread OOTP awhile ago, mb. He's situation still wasn't the same as Snape's tho >.<