Depending on how you count, something like 96%, 94%, 65% or 87% of mainstream media employees lean left. Of course this matters less and less as customers tune out and their influence wanes.
Yes, educated people tend to lean left, since the right is so anti-intellectual. But virtually all media in this country (both social and legacy) belongs to the far right pedophile oligarchs currently running this country to the ground to fatten their pockets.