“Just like 99% of all newspapers and media outlets today.”
...but in those glorious days, they were honest and open about it.
In my state (Washington) the Seattle area had two papers - one that catered to the left and one that catered to the right. As with many things, changes came when the owners sold the right-leaning paper. And with the new ownership came a stealthy shift to the left. Within six or seven years the two papers were virtually indistinguishable and the right had lost its voice in the region.