there are cringe worthy publications on the left. Huffington Post, The Young Turks, Jezebel, etc. They are hyper-partisan, screechy, shrill, unreasonable, gossipy, (nearly) empty spectacles in their own right but I don't know of a single one of them that is even halfway as far off the deep end of "motherfuckin lizard people aliens are running satanic child sex slave rings out of a pizza restaurant" that the infowars style conspiracy stuff gets into.
and Mother Jones is nowhere even on that axis. it's a higher quality publication with a deliberate (and publicly announced) editorial bias.
I'm pretty sure I've seen some cringe-worthy publications on the left as well, but it's certainly more common on the right.