I am just going to note that many societies have had disputes about how best to manage and appoint an independent judiciary. Perhaps the most well known such incident in the U.S. involved the 1801 Judiciary Act, Adams' midnight judges, the Repeal Act, and the 1802 Judiciary Act--culminating in Stuart v Laird (1803), which (according to the standard histories) upheld the power of Congress to abolish lower federal courts notwithstanding that the judges on those courts had good behaviour tenure.
A less well known American incident involving the manipulation of the courts by the elected government took place during the Civil War...when Congress abolished the (federal) Circuit Court for D.C circa 1863. Why was this done? To get rid of troublesome Judge Merrick. Merrick was an Article III judge, and Lincoln had already stopped his pay! Merrick was using habeas corpus to let people out of the army during war time! See Murphy v. Porter (1861). So his court (along with his colleagues) had to go to save the country. Of course the "people" Merrick sought to remove from the Army were apparently legally still children who had volunteered and lied about their age in order to enlist--thereby separating themselves from their parents, who brought habeas corpus actions to retire their children from further Army service.
I have read lots of histories of these events--some contemporaneous and some modern. I don't remember anyone using the language of "purge". I must have missed that. And notwithstanding the intervention by the elected arms of the government manipulating the judicial system, our country went on nicely absent any apparent authoritarian turn. (Unless of course, you think Jefferson and Lincoln were authoritarians.)
Arrayed against the policy of the elected government of Poland (which ran for election twice on this policy) is: the EU Commission (not elected), the decisions of the European Court of Human Rights (not elected), the Council of Europe / Venice Commission (not elected), and any number of Polish judges -- all appointed by a process wholly insulated from democratic control. But I repeat myself.
I cannot prove this, but I expect if during our domestic squabbles involving the elected arms of the government manipulating the federal courts (circa 1802, and again circa 1863, or even today in relation to court packing) a bunch of international organisations told us what to do, such interventions would not have been (and will not be in the future) very welcomed, and might very well have made (and will make in the future) normal political compromise less likely.
"Purge". If you want more Trump ... but I repeat myself.
Seth Barrett Tillman, Poland's Judicial Crisis: My Post on CONLAWPROF, New Reform Club (July 4, 2018, 1:49 PM), https://reformclub.blogspot.com/2018/07/polands-judicial-crisis-my-post-on.html.