I have read some Aquinas, but like most other philosophers (and almost everyone in general), I think he makes some bad assumptions up front, which spoils all the arguments that would rest on them. And because of that, I find it very important to always start, essentially, from square one - because most people’s prior assumptions simply and quite frankly aren't good enough to use as our starting point.

In the context of your comment here, I think you're getting ahead of yourself with the assumption that humans "should be ordered to prudence, justice, and charity". To me, that's not a good assumption. We have to start closer to the root of how we know anything, or how we begin to place value in anything. Which is to say, we have to start with desire and fear, pleasure and pain, happiness and sadness - those most fundamental perceptions, without which we would have no use for the words "good" and "bad" or "evil".

And it can be tempting, from that point, to take something of a utilitarian stance, and try to "maximize" pleasure or "minimize" suffering. And in the context of a large group of sentient beings (e.g. humans) who are mostly empathetic, and mostly want the same things (e.g. food, shelter, connection), and for whom the world very often rewards "positive sum" cooperation over "negative sum" competition, the utilitarian philosophy really does offer a good rule of thumb.

But things fall apart when resources are unsolvably scarce, or when some people's desires are unavoidably antagonistic to those of other people (e.g. sociopaths). And in such cases, our traditional route is to label such antagonists as "evil", but the fact is, that they are just as "natural" as anyone else. So what's really at play, when broader society calls its enemies "evil", is really nothing more than a tyranny of the majority.

That's not to say that broader society "ought" not protect their own interests, or that there is something "wrong" about them fearing and fighting with those who might do them harm. That's perfectly "natural" too. All I'm saying is that although the crowd tends to think of themselves as more morally "correct" or "natural" than their antagonists, in fact, they are just more numerous.