Who was John Hercanus? He was the of Judas Maccabees. When the Jews were released from captivity from Babylonia they found that the Edomites had moved into their land of Judea. John Hercanus led the Israelites to victory over the Edomites. Hercanus unfortunately left the Edomites stay if they would get circumcised and follow Jewish Law. Of course this was for public consumption only.
The Edomites were as evil as ever. King Herod the Great ordered all Jewish males killed who were two years old. That certainly is not the action of a true convert. King Herod was an Edomite as well as his son Herod Antipas. Here are two pieces of evidence to substantiate the previous statements.
1. from then on they [the non-Israelite Edomites] constituted a part of the Jewish people, Herod [King of Judea] being one of their descendants. "EDOM (Idumea), The New Standard Jewish Encyclopedia (Garden City, NY: Doubleday & Company, Inc., 1977) p. 589
2. …they [the Edomites] were hereafter no other than [non-Israelite] Jews. Flavius Josephus, The Antiquities of the Jews (Grand Rapids, MI: Dregel Publications, 1960) Book XIII, Chapter IX, Verse 1, p. 279.