That's not the issue, many of those people (on both sides) would prefer to get on with their studies. For some it might even be why they came here to study.
As an international student, the argument that some of our students are from overseas and therefor international issues affect us due to the impact on them... just doesn't hold water. Issues like visas that affect the majority of international students ARE an issue worth spending the students' union's time on. Issues such as whether Australia becomes a republic are (and I say this as an Australian) frankly none of your business (probably why you don't discuss it much).
If you want a random international issue that affects many of our students, and is primarily "your" (that is the UKs) job to fix... why are Commonwealth citizens treated as second class citizens compared to EU? Is the Commonwealth worth anything today? The evidence suggests not. I don't want a vote for your parliment, I want this joke of an "entry clearance certificate" (the visa that's not a visa but costs the same) abolished. When you've got that sorted we can talk about international student fees and should there be a third catagory for commonwealth citizens.