Did the argentinians commit atrocities? No.
Did they break accepted treatment of civilians in war zones? Yes.
Did they mistreat civilians? Yes, although not too badly.
However their plans were somewhat more drastic, and certainly the record of some of the officers posted to the islands doesn't lead to any confidence things wouldnt have got a LOT worse. Especially if, as a result of the task force not arriving or arriving late, the British resort to their traditional tactics of raids and harrassment, with consequential pressure on the civilian population.
So as the tales get out of how the islanders are being treated gets out, just what do you think the reaction of the British will be? Apart from the usualy professional aplogeticists and objectors, it will be to give the Argentinians a bloody good kicking. The harder the better (actually the reaction immediately after the invasion was already to do that, its not just going to quietly go away....)
While its true that governments dont always take account of what the people think, the day after the invasion the senior Conservatives (the people in the party who make and break Prime Minsisters) told Thatcher quite bluntly that if nothing serious (eg a taskforce) was done, the government would fall as a result of backbench (and some not on the backbench!) revolt.