No, I think you're onto something. It's interesting in that I think there's a parallel between what you're seeing in why these kids like the Sopranos and the life portrayed on The Sopranos. As others have noted the show does a good job of portraying the first gen imimgrant take on American life, and arguably that's about getting respect. How you get it doesn't really matter, or if it's fear, not respect, it doesn't matter either. Getting it is what counts, and Tony certainly gets it.
Like you I don't think these kids are apprenticing to be stone killers, I suspect the episode when Tony took his daughter to the U was a drag to them, as was most of the fourth season. Like any good drama there are universal themes that people can pick up on; the connections between them, either direct or ironic/paradoxic come with age and taste. I think the kids you're talking to are seeing one theme in the show but not seeing how it connects with others. My best guess anyway, ahem, not having talekd to them myself.........
I don't pretend the show is for everyone, but it is more than just a show about gangsters, just as The Godfather wasn't just a story about Italian immigrants trying to make good. BTW, according to at least one person I've talked to Puzo based the behaviour of the character Don Corleone on his mother. Kind of makes sense when you see Tony's mom at work.
PC
N P Childs
'I'm Mister Bad Example, the stranger in the dirt, I like to have a good time and I don't care who gets hurt'.
-Mr. Bad Example, W Zevon