Outlawing the naming of death camps is definitely a measure by the Polish government to sweep its dark history under a rug. Allowing names to be assigned to death camps will put a certain reality to it and perhaps force their citizens to look at the horrors their ancestors and government inflicted.
Poland is attempting to hide some of the more darker events in the country's history. Poland is outlawing the naming of death camps, which is a form of censorship. The goal of this new law is to cover up past atrocities that would make some citizens and the country look bad in the eyes of the world.
Although the law is extreme and unnecessary, it is simply to avoid associating Poland as the creator and operator of concentration camps built by Nazi Germany that happen to be on Polish soil today. It isn't meant to hide the fact that millions of Jews, Poles and other races were slaughtered in concentration camps placed by Nazi-Germany onto Polish soil, but to clarify that these were NOT Polish and that the government never agreed to this. The Polish Government did not officially surrender or co-operate with Nazi Germany (excluding 1933 non-aggression pact, which was long before the war and meant to stop another war with germany), instead, Poland remained as an underground state.
Poland is simply trying to address the problem of foreigners associating the Polish people with "running" these death camps. While outlawing the naming of the death camps is an extreme measure, it is not attempt to whitewash the camps out of history. It is simply an attempt to avoid the association with being the creators of the camps.
The Nazis occupied Poland during WWII and operated "death camps," such as Auschwitz, within its borders. Poland isn't trying to hide the fact that Jews were murdered in Poland. Rather, Poland wishes to clarify that these were not Polish death camps. They were Nazi death camps and only happened in Poland because of the Nazi occupation.