how is the government actually breaking the law
Law is not only what gets published in the Journal of Laws.
Gumishu, let's put it another way. You mentioned before that you live in/next to the forest. The local PiS man comes and decides that your house would make an ideal cabin for his daughter, so he brings a lawsuit using faked documents to prove that your house actually belongs to him.
The judge appointed to the case was appointed by PiS, and you lose the case quickly. Same happens with the appeal, and the Supreme Court (led by a PiS appointee) refuses you the chance to appeal there.
The court orders you to leave, enforced by the police. You complain to the PiS public prosecutor, who decides you have no case as it was all legal.
That's exactly what was happening in the PRL, and it's why independent judges are so important. The system isn't perfect, but having judges dependent on politicians is the worst possible outcome.
And please, don't tell "it won't happen to me" - that's the same thing that many other people believed before bad things happened. When it happens, you'll be the biggest supporter of the opposition, but it won't bring your house back.
Why do you think having one political party in control of the legal system is a good thing?