No, it's showing an acknowledgement of reality. Just like the countless other news organizations that have either never before endorsed a Democrat doing so for the first time, as well as USA Today coming out for/against a candidate for the first time ever.
These papers are not all spontaneously deciding to embrace liberalism. They're embracing reality, and the reality that Trump is largely the antithesis of traditional conservatism across the board, barely coherent when required to speak above a third grade level, and god damn terrifying.