Merkel leads a party in the ‘Christian Democracy’ political tradition:
Christian democracy is a political ideology which emerged in nineteenth-century Europe under the influence of conservatism and Catholic social teaching, as well as Neo-Calvinism. It was originally conceived as a combination of traditional Catholic beliefs and modern democratic ideas, and it grew to incorporate the social teaching of other Christian denominations, such as the Lutheran Church and the Reformed Church. After World War II, the Protestant and Catholic movements of the Social Gospel and Neo-Thomism, respectively, played a role in shaping Christian democracy. Christian democracy continues to be influential in Europe and Latin America, although it is present in other parts of the world too.
In practice, Christian democracy is often considered centre-right on cultural, social, and moral issues (and is thus a supporter of social conservatism), and it is considered centre-left “with respect to economic and labor issues, civil rights, and foreign policy.” Specifically, with regard to its fiscal stance, Christian democracy advocates a social market economy. In Europe, where Christian democrats defined their views as an alternative to the more leftist ideology of social democracy, Christian democratic parties are moderately conservative and centre-right overall
As such, her “social conservatism” in this respect is neither a U-turn nor a mere ruse to appeal to right-wing voters in view of modestly rising support for the AfD, although that will naturally be playinh on her party’s collective mind. This policy was actually agreed at her party’s convention back in August. So nothing new, its just been picked up late by the media.