I used the expression to correct for bias, which is a collocation coming out of, I would guess, statistics (see for example: https://ell.stackexchange.com/questions/142875/what-does-to-... ).

What I meant was that if you're aware that The Economist has a clear ideological lens through which it sees the world you can take that into account and take its comments with a grain of salt. Initially I was not aware of their clear ideological stance and I took it to be an objective publication.

This being said it's probably not possible to have an objective publication, so it's better to read one that is written competently and subsequently correct for its bias.