They say that Israel should "return the occupied territories" which, depending on who you are talking to can mean one of several things. But it probably refers to territory that was occupied by Israel outside the 1967 borders when in 1973 various neighbors attacked Israel and tried to kill everyone. But they failed and Israel ended up (very controversially) with a variety of contested territories.
I am not going to pass judgement on what Israel should or should not do without much more research and at least one site visit. But I have no trouble observing just how self-serving and hypocritical those who tell Israel what to do here really are.
Let's review a few examples of "occupied territories".
1. Are you from Australia and you criticize Israel on this topic? Please have the decency to first return the occupied territories to the indigenous people of Australia that you stole them from.
2. Are you from Great Britain? How dare you criticize another nation given your amazing history and the current occupation of Northern Ireland?
3. Are you from or living in the United States? We have occupied territories here on so many different levels, it might make one laugh if it were at all funny. The USA was involved in a war with Mexico and claimed as a result Texas, Arizona and New Mexico. Then of course there is the whole story of California. Puerto Rico? Guantanamo? Hawaii? Guam?
4. Are you from Colorado? The Apache, Arapaho, Cheyenme, Ute, Shoshone and Pueblo people would like it back, if that is all right with you.
5. Connecticut, New York, Massachusetts, Virginia? Return the occupied territories.
6. Perhaps the Japanese will want to return Hokkaido to the Ainu?
7. Perhaps the People's Republic of China would like to free Tibet or Uigher?
8. Perhaps the Turks would like to stop their war against the Kurds and allow a free Kurdistan to come into existence?
9. Perhaps Russia would like to return great chunks of Siberia to their indigenous people?
And on and on.
Whether Israel should or should not return the West Bank is debatable. But before you go around telling other countries what to do, I think it would reasonable to expect you to clean up your own act first.
Ainu People on Wikipedia