To denunciate researchers as having a "political agenda", because their opinion does not fit into the own political agenda, does not sound very honest to me.
<Irony>Also many academics in Europe say, that climate change is happening -- shame on Europe! What academics from Europe say, must be wrong!
And of course "leftist views" are also wrong all the time. Don't listen to those that are called leftist or similar in Fox News or other trustworthy channels. </Irony>
Other times, however, ideas become widely accepted, even entrenched, without any real evidence. Such entrenched beliefs often arise because they support particular political or moral agendas; if the beliefs are falsified, the moral agenda will be threatened.
The academic views on inequality fall firmly in the latter category.
I don't mean New Keynesian partisans like Paul Krugman. Actual Post-Keynesians (particularly Kaleckians and MMTers) and Marxians are rare, though perhaps growing as a result of the aftermath in 2008. Nevertheless, the Great Depression also had major economic cults emerge like the Townsend Plan and Social Credit which since receded.