“Does lo sirtzach change as well?”
Throughout the 1900 year Golus, vulnerable Jewish communities whose existence was threatened by traitors had to take action for their survival. See the Gemara in Gittin that action against Bar Kamtza should have been taken, but was not taken due to the excessive piety of Rabbi Zecharia ben Avkolos.
Now that we have a State the need to take such action against traitors is actually less.
But in 1924 what was published in London’s Daily Express could put Jewish communities at extreme risk. Look up their March 24, 1933 headline. Type in a search engine “
daily express march 24″.