Should the walls be plastered or not?

Ive moved into a rented flat from Places for People, and all the rooms were decorated from previous occupent, anyway ive striped wallpaper off in main bedroom and 3 of the walls are plastered and the outside main wall is only got plasterboard on the walls, no top plaster skimmed on. All the plasterboard joints are visable too.
I phoned places for people to complain and have it plastered as it was clear it hadnt ever been done since the place was built about 10 years ago.

They phoned back today and said, on new properties the walls are just plaster boarded with a special plasterboard and the joints are taped over so you can paint straight over them or wallpaper them so in effect he was saying they dont plaster over plasterboard despite the rest of the walls being plastered.

Should this wall be plastered and not just left with plaseterboard on?

I feel like they just cant be ars*d to come do the work.