Shulchan Aruch, Orach Chaim 690:16 says
One must say "Accursed is Haman, blessed is Mordechai, accursed is Zeresh, blessed is Esther, accursed are all who hate HaShem, blessed are all who believe in HaShem," and one must say "And also Charvonah should be remembered for good."
Other editions of the Shulchan Aruch have different versions of the bolded phrases. However, in many congregations, and in the ArtScroll siddurim, these words are completely omitted. Why?
There are, in fact, a wide variety of variant forms of this passage in Shoshanas Yaakov (which is itself something of a synthesis of earlier sources). The general assumption appears to be that this passage was modified, and even removed, due to "censorship" (which can mean actual censorship by non-Jewish authorities or self-censorship to avoid provoking the non-Jewish authorities). This censorship affected not only the text of the siddur but also the text of the basic sources, including the Tur, Shulchan Aruch, and even the Talmud Yerushalmi. (Thus we find variant texts in this regard in these works as well.) (See, in no particular order, the discussion here, here, here, here, and here. And some relevant source material here.)
Given the difficulty in ascertaining the correct language, and the fact that there are concerns about some of these versions, it isn't surprising that some publishers continue to omit the passage.
