The issue with that is you're sort of leaving key parts out. Have you considered that OP might be a bit wishy-washy herself? For instance, there's a key statement here:

He says that it just makes sense to do it now. I do agree with this, generally, but not entirely.

OP doesn't agree with him but she definitely doesn't disagree with him entirely either.

If that's how she's portraying herself to him, and he wants kids he, may think she's on the fence. It may well be that she's not ready to be a mother but he's pushing her because she isn't being clear about what she wants out of life.

Viewed this way, it's a communication issue which she can resolve by being resolute and firm in what she wants: i.e. "LISTEN. I only want kids after I've graduated and we're married! End of discussion." That single statement will produce a reaction from him: a reaction which will be far more revealing than calling him a 'skeeze' and a 'selfish f-ck'. His true motive can only be discerned by communicating with him: not by haranguing him.

And guess what? Maybe you're right: maybe he's a prick that wants her for her body and her child bearing hips: he'll demonstrate this clearly by continuing to push her after she's been clear about her desires. In this case your assessment is spot on.

But if she says to him what you're proposing, and it turns out she was unclear to start with, all it will do is alienate him further and muddy the waters with unnecessary hurt feelings. If she goes from being wishy-washy to suddenly calling him crass names, that might be a bit of a problem, no? He might feel that she suddenly doesn't want children with him at all, when she 'sort of' did before. It'll undoubtedly lead to unnecessary animosity, further miscommunication, and maybe even a breakup. For all you know he could have been a great father and husband that was just being understandably insensitive to her unclear desires.

Disliking him because he's doing something unpopular (being with a younger girl) and is acting like a dunderhead (getting pushy about something sensitive) is understandable.

But smearing him, an suggesting that she OP should do the same, on the basis of a few 'vague-at-best' descriptions is a bit premature.