This is the result of comprehensive cuts to education funding. Many assistant professors make less than postdocs, which has led to stagnation in postdoc wages. The NIH is trying to increase postdoc salaries for all funded grants, but there's a lot of pushback from professors who contend that postdocs shouldn't make more than more senior positions (i.e., professors). Prioritize funding higher education and this problem will start to ease.
Also though, additionally, cost of housing is not a great example how postdocs are underpaid. Yes, they are, no doubt. But cost of housing has been increasing disgustingly over the past... forever? I am sure Dublin is no stranger to that. It is an issue but a separate one.
We have a postdoc union here. Similar unions exist or are forming at competing schools. Hopefully experiences like those in the article become less common.