There are usually "student council" programs that give a handful of elected students a regular audience with administrators, but most of these programs don't have any teeth.
Graduate student council programs in particular are often built as a compromise to prevent the students from forming an organization with greater efficacy.
Anecdotally, some PIs I know have had to directly contend with rising organization among students and handed out a raise and a bonus to their labs.
In Sweden, students and graduate students are well-organized/unionized, but the situation for PostDocs and other post-doctoral fixed-term employed academics is dire nonetheless, in particular for immigrants, for whom the fixed-term contracts cause problems with their residence permits, considering recent changes in immigration laws.
And recent changes by the government have actually made it worse. The irony is that the unions have been campaigning for these changes. It's really weird how unions think that requiring that postdocs must get a permanent position after 4 years would somehow lead to them getting those positions, while there is no more funding from the government, so no permanent positions are being created. I mean in our department academic faculty have to find 50% of their salary plus ~80% overhead from external funding. Really universities in Sweden tend to be more like research hotels, with lots of regulations that you have to follow.
It's not weird at all, considering where the unions are coming from. This is from Finland and from 10+ years ago, but from what I remember, the Swedish way of thinking was similar.
According to the spirit of the law, all jobs are permanent by default. Fixed-term positions require a valid reason. A project (such as completing a PhD) is a valid reason. The availability of funding is not. While an externally funded research project could be considered a project, it's reasonable to assume that someone in the university will apply for funding for similar research in the future. Because someone is planning to continue similar projects in the future, the need for that particular externally funded researcher does not end when the initial grant runs out. And even if those applications fail, the university still has other money for paying the salary. The employment should continue until the university decides to reduce the number of people doing that kind of research permanently.
In principle, it should be categorically illegal to hire fixed-term postdocs, but the academia does not work like that. Because the union is a union first and a representative of specific people only after that, it's extremely unwilling to let go of the "all jobs are permanent by default" principle. There must be a compromise that allows the international standard practice of hiring postdocs for a few years without letting the employer to chain fixed-term positions indefinitely. Whether 4 years is a good compromise is debatable, but it's easy to see why a union would want something like that.
Also, from a Finnish perspective, Sweden has a reputation as a country where it's relatively easy to get a permanent academic position.
I believe you are thinking about representative bodies (maybe the equivalent of UA for undergrads, or GSC for grads, at MIT) while the union in the news is employment-based and is the sole legally recognized entity to negotiate salaries, employment conditions, etc. on behalf of MIT graduate students.
Graduate students are employees of the university. There are usually other unions at universities for employees, and undergraduate students working in universities can sometimes be in those unions as well, but graduate students as employees face some unique circumstances due to their employment and as a result often form their own union.
Traditionally for better or for worse, undergraduate representation comes by way of a student council, with a single person elected to a chair on the larger university advisory council (the structure can be different depending on the university, I'm generalizing).
There’s a distinction in the US between fully-funded PhD graduate students (who receive a stipend contingent upon research/TA work in an employment relationship) and professional/masters students who pay tuition, even though the latter group is also referred to as graduate students.
Note that for instance if you're there with a fellowship and aren't getting a partial RA/TA assignment as well then you're not eligible. I know that some masters students pay for their tuition, so they might not be eligible either since they're not getting a stipend.
Including undergraduates, who are primarily paying consumers, would have muddied the waters. Graduate students are clearly workers under any definition.
Masters programs are typically where you pay tuition and receive training via classes. PhD programs don't have much classwork and instead are positions where students are paid by the university but are expected to perform labor to produce original research.
Hm, here in Hungary PhD students can opt to do zero teaching[0], and also the tuition is 4500 EUR/semester (and students from the EU can apply for grants that covers 100% of tuition). And on top of all this it's possible to work for the university, which apart from the salary also results in the elimination of certain costs (eg. if someone is not employed by the university they have to pay to have their thesis examined and pay for the exam committee or something).
All Ph.D. programs nominally charge tuition, but hardly any students (at least in STEM, don't know about elsewhere) pay it. They get a stipend plus a "tuition waiver".
Graduate student council programs in particular are often built as a compromise to prevent the students from forming an organization with greater efficacy.
Anecdotally, some PIs I know have had to directly contend with rising organization among students and handed out a raise and a bonus to their labs.