[coldtea]

Well, it's not about being monotonically the case year-over-year, but the overal "weighted average" direction of the vector pointing towards less right-wing.

Obviously e.g. the Weimar youth was liberal and partying and then Germans turned to fascism in the 30s. But that was a temporary setback, not the general direction of change. Overall Germans of 20th century are much less conservative and right wing than Germans of the 19th century, same for 18th century and so on.

It's also not really about antiquity, but about the arrow of modernity (say, 16th century onwards). The concept of left/right wing is not something applicable to Pagans and Romans (although both were way more "right wing" than the Christian era if we try to judge them under this anachronism).