That mistake was made by the UN not the Palestinians. The UN imposed its will on them. It wasn't democratically decided. It wasn't the will of the people. A handful of colonial powers carved up the world yet again. The UN was in its infancy having emerged from WW II and as a residual of the League of Nations it made a mistake for which it hasn't yet atoned.
Islamic State militants blow up ancient Arch of Triumph in Palmyra (Reuters)
from the article: The Palestinians must not repeat their mistake of 1947