Non-PRO Danish to English Social Sciences Education / Pedagogy

From an article concerning the teacher training process in Denmark: "...blev fysisk afstraffelse et udtryk for noget gammeldags. At det tog så forholdsvis lang tid at slå igennem efter 2. verdenskrig skyldtes dog ikke mindst modstand fra lærere. Disse lærere fandt, at korporlig straf kun anvendtes sjældent, men dog var et nødvendigt sidste magtmiddel, der ville dø ud af sig selv, når og hvis behovet for det døde ud. Fortalere havde cirkulæret til gengæld blandt yngre lærere, i pædagogiske kredse og nok så vigtigt blandt socialdemokratiske og radikale politikere."

I have tentatively translated the bulk of this passage as: "...physical punishment became an expression of something archaic. That it took such a comparatively long time for this to be put into practice after the 2nd World War was due—not least of all—to opposition from teachers. These teachers found that corporal punishment, only employed rarely, was still a necessary last resort that would die out on its own, when and if the need for it died out. [In retaliation?], proponents had circulated among younger teachers, in pedagogical circles, and even more importantly among Social Democratic and radical politicians."

However, I think I'm missing something here. Who are the "proponents?" Supporters of corporal punishment, or supporters of the abolishment of corporal punishment? I'm not even sure "retaliation" is the correct concept here... Any help will be greatly appreciated!