Well if Ukraine is allowed to take back Crimea, i don't see why Palestine wouldn't be allowed to take back what is theirs.
The Arab states invaded Israel multiple times, though, whereas Russia is the one that did the invading in the Ukrainian case so the comparison doesn't fit.
The creation of Israël can also be seen as whites/Europeans invading the Arab world.
Use your brains for this one: what did the whites/Europeans do to these invaders thar could've caused their invasion?
And you didn't answer the question: which territories should Palestine be allowed to take back?