Seeing a lot of people who seem adamant that the problems with exploitation of international students and temp migrants in the workplace can only be solved by stopping them from coming to Australia.

This is an extremely facile argument and, among other issues, does nothing to improve the plight of students who are already here. The government should take more active steps towards implementing the recommendations of the Migrant workers taskforce. https://www.ag.gov.au/sites/default/files/2020-03/mwt_final_report.pdf

But honestly, that's not going to be enough. We have to stop thinking that the only way to get migrants any certainty is to make them permanent residents. There are migrants for whom, PR isn't the end-game. So what's the strategy there.

The math of it doesn't work out either, there are 1.5 mn temporary migrants in Australia with some kind of work rights and our intake is 160k a year (between family and skilled visas). We must ensure that temp migrants have the same workplace entitlements available to Aus workers

We need to level the playing field between temp migrants and the rest of the workforce. This will likely involve removing restrictions that increase the likelihood of exploitation; removing the 40 hours a fortnight restriction for international students (on the basis that it ....

causes a lot of harm in attempting to achieve its objective).
Fact remains that there are students who have had to pay a lot of money to come to Australia, sometimes to unscrupulous loan sharks in their home country. Their demand for work will exist.

Removing the 88 day regional work requirement for working holiday makers wishing to apply for another WHM visa will also help reducing the amount of control unscrupulous employers have on whm visaholders

Levelling the playing field between Australian workers and temp migrants, and ensuring that they can avail of the same safety provisions seems to me the better way prevent exploitation (as opposed to stopping them altogether).

Highly recommend this report on this topic from Unions NSW
https://www.unionsnsw.org.au/wp-content/uploads/2020/08/NWLB_survey_results_aug_2020.pdf