A lot of instances are set up explicitly so, and there are many vocal users both on those instances and elsewhere.
Dip into posts on #politics or #economics (or even as an undercurrent to a lot of other posts) and you’ll find some very extreme #lefitist and #AntiCapitalist rhetoric. It can seem like the fediverse skews far-#left the same way “#AltTech” platforms skew far-#right.