@Jorsh @Miriamm @angiebaby When I was an undergraduate, I recognized that many of the articles I was finding in literature searches supported leftist policies. And so I tried, really hard, to find articles supported right wing views.
They weren't there. But there are nuances.
If you lean right, how interested will you be in social issues? Your way of knowing will be some way, somehow ideological. You might be satisfied with "God's plan" (even if the entirety of the Old Testament stands in refutation). You might be satisfied with capitalism (as "God" takes care of the "select"). You might even be satisfied with Donald Trump's used toilet paper.
Needless to say, none of this passes muster in academia. So you will find academia a hostile place. And because you really don't care about the differences, you might label it "liberal," "socialist," "Marxist," "communist," or even "fascist." But you certainly won't pursue advanced degrees and even if you do, academia is about the last place you'd want to work.
Which is to say that the perceived "leftist" bias in academia is in part due to self-selection. There are other problems as well: A methodology that favors empirical data will be scorned as embracing a way of knowing that, in conservative epistemology, ranks far below the way conservatives think things should be (their "truth" is what they want it to be and, yes, this is the naturalistic fallacy). And there's not really a good way to tell how much of it can be attributed to which factors.