Now 46 and editor of Midrasz, the Warsaw-based magazine of Poland's 10,000 strong Jewish community, he faces another uphill struggle: to disentangle the web of stereotypes that has corrupted the intense, centuries-old relationship between Jews and Poles.
GEBERT'S OFFICE is a sort of open-house for anyone who has an opinion about Jews and Poland, which is most of the population. The week starts at 8am on Mondays, when he opens up the office, and waits for the first reader to walk in.
"I get a lot of visitors, the readers come straight in. On a Jewish newspaper everyone wants to do your job for you. They tell me `OK, now I'm going to explain to you what this newspaper should look like'. I get buttonholed all the time."
And there are always surprises. "Recently a very military looking man, formally dressed, with a gravelly voice came in. He is a reader of one of the far-right papers. He told me that the paper had run an attack on me, and he had written a reply defending me which had been published. He barked that he didn't want the money, put the fee on the table, and left. Another visitor, an elderly gentleman from Israel brought me material that appears to show that a Polish MP had been part of a gang killing Jews during the war. That was something that I take very seriously and will follow up."
MANY HOPE that the Pope's visit to Poland this month, and the recent removal of the crosses at Auschwitz can help heal the historical wounds. That relationship between Jews and Poles is still so abnormal that the Jewish community even runs a help-line for Poles who have discovered that their ancestors were really called not Kowalski, but Cohen and don't know how to cope.
As a trained psychotherapist, Gebert can help. Mid-week evenings are often spent on the help-line.
"We are listed in the newspapers with the other problems: battered wives, alcohol abuse, Jews. Sometimes I hear a story that chills me to the bone. A woman called me with a very composed voice, speaking in the kind of flat monotone that shows she is on the verge of hysteria. She had been born Jewish but didn't follow the religion or even identify herself as Jewish.
"She had met a guy at university, they had married and had kids. She never felt comfortable at family parties, because the in-laws were very rich but very uncouth and unsophisticated.
"One day they got drunk and revealed how they had got their money: from robbing Jews during the war and turning them in to the Gestapo. Her husband had known all along.
"She divorced him and immediately broke with the family. She called the helpline because she has a new man now, but each time he took her to meet his parents she could not enter their house.
"It's a terrifying story, like a rape. You cannot rebuild a person after that because their trust in the world is lost."
AS A religious Jew, Gebert does not work on Friday night or on Saturday. This is a holy time, devoted to the family and to God. "Friday and Saturday are the most important time for me, the Sabbath. This is a truly sacred time, we turn off the telephone and we don't travel. I go to the synagogue on Friday evening and Saturday morning. My children usually watch television. I don't approve but I don't argue with then. It's a `don't ask, don't tell situation'. On Saturday afternoons I read or study."
OTHER WEEKDAYS are spent travelling, often to the United States, to lecture on Jewish-Polish relations, or teaching Judaism to Catholic Poles. "Jews do not have the right to be as prejudiced as everyone else and the kind of prejudice many Jews have against Poland is unwarranted and misinformed. So I always enjoy it when people see there are other ways of looking at things.
"Sometimes I teach Talmud [commentary on Jewish law], almost exclusively to non-Jewish audiences. Talmud has a bad reputation in Poland but it's a very exciting intellectual discipline. Non-Jews are very interested, because attitudes here towards Jews have changed.
"Until recently the very word `Jew' could not be pronounced, we were described as being of `the mosaic faith'. Now it is possible to have a rational discourse about Jews."
TEN YEARS on from the collapse of Communism, Gebert has mixed feelings about his dissident days. Sundays, a quiet day away from both the office and synagogue can be a time to reflect on the massive changes that have transformed Poland.
"All of us expected to end up in prison. The greatest fun was that we wrote what we thought and nobody stopped us. But there was so much wasted time. The most intelligent people used their brains for the most mindless purposes, university professors working out how to avoid a police tail.
"Our newspaper had a circulation of 15,000, with seven regional editions as well. We printed it on silk-screen because you don't need any spare parts and you can hide everything easily. I still think that it is the obligation of every citizen of a democracy to know silk-screen printing. Just in case."