There's actually a page on the Raising the Bar that unsolidified the misconception that the Combine are into nationalistic propaganda posters, explaining that the Combine don't need such practices because humanity itself is already aware and fearful of their presence.
HL:A sorta retconned that with their new propaganda posters (Combine for Safety, Human Science, Report the Vort, Etc), but that can be excused with just being a brief loyalists' art project... Or with Breen himself discontinuing propaganda campaigns 'cause it was dumb.
Without delving too much into speculation and headcanon, an explanation provided by some developer commentary about their reasoning for the absence of Breen in HLA was chalked up to him still competing with other Combine-sympathetic factions for the top dog role 5 years before the events of Half-Life 2. [
Source]
These entities, largely unknown ex."City 17 Security Council," may have played a part in cultivating the more humanist-driven propaganda posters we see in HLA.
All in all, you could perceive the existence of such entities more as sparks of voluntary human initiative, neither countering nor directly supporting. It's sort of like, "Oh, you're creating funny art and committees sympathetic to our occupation? Go ahead, we don't care," rather than some fantastical humanist Willy Witworks government with numerous levels of human bureaucracy and institutions.
