That could easily fill several PhD theses. I've already got my hands full with my own. But if you're interested, you might read Catharine Edward's the Politics of Immorality in Rome, which while not focused on Suetonius in particular, does get into the heart of a lot of Roman moralizing discourse and the way it was used (and how differently it was constructed.) The main thing to keep in mind is that where we today tend to explain things in terms of economics, politics, or psychology, for the Romans, all those things were discussed in terms of mores. And, considering it was the primary mode of discourse, Roman morality was very complex.
But, to give a very, very simple example, there's a line in Cicero about Caesar where he says something like, "you wouldn't think such a man would be the type of guy to scratch his head with one finger" which makes absolutely NO sense unless you understand it's a reference to effeminacy... which while a slur, is more than that, and there's more going on. Effeminacy for the Romans was conceptually related to a lot of other things - and not necessarily the things we'd associated it with- especially in terms of luxury and leisure, which were considered the symptoms and cause of immorality, and had links to the idea of the corruption of the state and the undermining of the mos maiorum. It was also linked with adultery, which tends to go against the biases of the modern reader. But for the Romans, it was a challenge to the power of the paterfamilias. Which, as a side note, was the purpose of a lot of Augustus' adultery legislation- not necessarily turning a tide against a presumptive wave of adultery (although writers were always claiming such, for the entire history of Rome, but there are reasons for that), but the legislation was basically a defacto usurpation of the rights and privileges of the paterfamilias, elevating Augustus in such a way that kind of brought all of Rome into his household and under his hand. So for him to be saying (or rather, for writers to be depicting him as saying) "you Roman fathers aren't doing your jobs and reigning in this immorality, which of course threatens the state, so I must step in and fulfill that role, aren't you glad for that" is never going to be a straightforward thing. Which basically is why modern ideas of Rome tend to be full of orgies and excess: the Romans never shut up about those things. But not because they were necessarily happening, but because they were coded in such ways that made them the common weapons of every agenda.