This is not exactly what Scandinavian social democracy is. There are differences between Scandinavian countries. In Sweden the established parties refused to cooperate with the Sweden Democrats which has until now delayed the decline there.

The reactionary nature of Danish politics is a more recent development. Denmark used to be a progressive place regarding economic as well as social issues. Basically the danish social democrats played themselves when the emergence of the far right populist Danish People's Party caused them to lose many of their traditional voters. Instead of standing their ground on the antiracist sentiments they once had they adopted a strategy of winning back voters from the far right by appeasing the DPP and trying to triangulate their way into a position that was racist enough that they would come back. Meanwhile the established Danish right wing saw the possibility to gain power by allying themselves with the DPP.

This led to a political climate where the major right wing parties gave the DPP and their racist views the legitimacy they once lacked. Meanwhile the social democrats, the major "left" wing party, didn't put up a fight but promoted a lesser racism instead. This leads to the Overton window shifting to the right and with it came the spineless social democrats.

The strategy didn't work well for the social democrats. Racists were voting for the real thing anyways. In 2015, following an electoral defeat for the social democrats the current Danish PM Mette Frederiksen became chairman of the party. She and the people around her understood that just being the lesser racist was not going to cut it. Racism had been the right 's electoral super weapon for decades. To cancel it out the social democrats had to be just as racist as the DPP.

The strategy worked. The commitment to racism coupled with strategic promises of welfare improvements to select voter groups and the incompetence and petty corruption of the incumbent right wing government gave the social democrats a landslide victory in the 2019 election.

Now we have a situation where Danish politics had become a competition between the right wing and the social democrats as to who can be the most racist. The parliamentary left can do very little about it. They are massively outnumbered, the social democrats can get comfortable majorities for the racist and reactionary stuff with the right wing and if the left were to force the government out of office by a vote of no confidence the result would either be a right wing government or another social democratic government.