I suspect they aren't linked. Societies have generally changed a lot in the past 100 years. Pre- and Post- WWI Europe are different beasts.
"As the epidemic raged in late August, when around 20 people were dying daily, the city’s bank director Carl Lignell withdrew funds from Stockholm without authorisation and requisitioned a school for use as a hospital (the city didn’t have one). "
..
"“What is interesting is that, after the epidemic, the state dropped investigations against Lignell and made tentative steps towards a cooperative approach to social reform. Issues such as poor nutrition and housing were on the political agenda,” says Hedlund. Anyone trying to date the inception of Sweden’s welfare state cannot overlook the events of autumn 1918."
You can argue about the causality but it's not clickbait in the sense that it interviews a local expert who is making a case that it was a significant factor.
Do you mean to suggest rich people are always hit as hard as poor people?
Social inequality does not make a pandemic to hit harder, for example the lack of rich people (reduced inequality) would not decrease the rate of infection of the rest of the population. A city with all poor people (low inequality) would probably be hit even harder, so the living conditions are a factor at amplifying the effect of a pandemic, inequality is not. Inequality in theory slightly reduces the hit if you assume the rich will better take care of themselves.