Yes but Ottoman rule should be understood to span many ethnic and religious groups. There was no "Ottoman people", the way you have, say, Germans. The Jews were there under Ottoman rule, for example (in fact the Ottoman sultan gave them independence in trade for a lot of money). So while there are long-time-there Palestinian bedouins, there are also Jewish bedouins, and even smaller groups like Druze or even Catholics. There were many semi-states under the Ottoman empire that have since warred and lost or gained territory. The British attempted to keep Ottoman governmental structures largely in place, and they failed badly.
Turkey was conquered by the Turks, from Greeks, Armenians, and various smaller groups. Big parts of it not that long ago (~1 century). Somalia was conquered from Ethiopia. Pakistan from India. Bangladesh from Pakistan. Hell, Northern Iraq was conquered from the Kurds ... by Arab Nazi's. Seriously. History can be funny at times.
Most of these conquests are younger than Israel is. Why don't we see people follow Indian demands for re-annexation (and religious suppression) of Pakistan? Pakistan demands the same of Bangladesh (and yes religious suppression. "There are no sects in Islam" is part of Islamic doctrine. There are no splits in Sunni Islam, but somehow Pakistan and Bangladesh don't belong to the same Sunni Islam ... and are hundreds of millions of believers each).
Ethiopia wants to re-annex Somalia (and restore religions to where they were 100 years ago), and so on. Hell, there exist Indian extremists that would like to see Indonesia annexed too. Oh, and unlike the Israel-Palestine conflict, India and Pakistan are threatening to nuke each other. And China is now threatening them too, also with nukes, so there's plenty of new trouble brewing in that neighbourhood. And we haven't even mentioned China ...
Is anyone seriously suggesting undoing the conquests? For one thing that would be extremely impractical and a massive operation, even if they would cooperate (and I guarantee there'll be war in every case).
Why is this conflict so important? Compared to the India-Pakistan issue, it doesn't affect very many people (Israel and Palestine, even together, are at best the population of a medium US city, India-Pakistan-Bangladesh is 4-5 times the size of the entire US)
But I think I do see some factors. Israel-Palestine is so very, very small that it is actually conceivable that the west actually does something about it. India-Pakistan? We have zero chance to play a meaningful role there. Also the Israeli consider themselves part of the West, so they actually want the approval of the rest of the West.