Saeb Erekat told these aides that Israel is entirely at fault for there being no peace in the region and that the PLO desires a two-state solution.
On the same PLO page header, you can see its logo, which shows exactly how interested the PLO is in a two-state solution.
I doubt any of the delegation bothered asking about that.
Similarly, today, the website of the PLO's Department of Public Diplomacy and Policy includes explicitly antisemitic content. It features this description of Jews (archived here) in a page dedicated to the major Zionists that they blame for the "Naqba" with antisemitic Quranic allusions:
انهم علو في الارض يذبحون ابناءنا ويستحيون نسائنا وما كيد يهود الا في ضلال ،الاجرام صفتهم والقتل لغتهم وهدم البيوت عرفهم وقلع الاشجار عادتهم، شخصيات يهود تجسد الاجرام والعتو ،لكن في هذه البوابة سنعرفهم عن قرب.
They acted with arrogance on earth, slaughtering our sons and leaving our women alive, and the plotting of the Jews is just delusions. Crime is their quality/attribute, killing is their language, destroying homes is their custom, uprooting trees is their habit. Jewish personalities epitomize crime and arrogance, but in this web portal we will get to know them from up close.Is this anomalous? Of course not. Official Palestinian TV, effectively run by the PLO, has dozens of examples of explicit antisemitism - often from PLO leaders themselves - every year.
The Fatah platform of 2009 remains in force, and it says that terrorism ("armed struggle") is their right, never abandoned and allowed, they claim, under international law. It also explicitly says it wants "preserve the refugee camps as a political witness" even on its own territory, a conscious decision to keep their own people miserable as political capital against Israel.
J-Street would never mention these facts. In fact, it would do everything it could to hide it.
J-Street pretends to be even-handed in these sorts of trips. They probably had the aides visit some dovish Israeli MKs. But their website, words and actions prove that they will bend over backwards to believe every lie the Palestinian leaders say and to be critical of every word the Israeli government says. There is nothing remotely balanced about them, and the congressional aides who attended these sessions weren't learning anything but curated anti-Israel propaganda.
(h/t Ibn Boutros)