ProPublica is extremely left-wing. That doesn't imply that their journalism is low-quality or inaccurate, but it does suggest that their choice of stories will be colored by that ideological/establishment-friendly bent. You won't see them investigating the political influence exerted by public sector unions for example.
Their X feed gives a pretty clear picture of that:
Their X feed gives a pretty clear picture of that:
https://x.com/propublica