The British record in Palestine is not as one-sided as you state. They were under vicious attack from Jewish terrorists during much of this period, and the Balfour Declaration stated that the Jewish homeland was not to be established at the expense of existing occupants of the land.
At least at first the Brits appear to have tried to balance the interests of the various groups, thus ticking off all sides. However, when one side is trying much more actively to kill you, it tends to affect your viewpoint of which side is in the right.
Somewhere around 600,000 Jews immigrated to Palestine from 1920 to 1947, some illegally. This was into an area inhabited by about 1,000,000 people, mostly Arab Muslims, in 1920.
As far as population change goes, this would be roughly equivalent to 120,000,000 people immigrating into the US since 1970. You may have noticed how upset some around here are at the present much lower rates of immigration into the US. It would be irrational to expect such levels of immigration not to generate resistance.
There is plenty of fault to go around. Brits, Jews, Arabs, everybody. The difference is that most Jews today want to live at peace with their neighbors and very darn few Arabs want to do anything but kill all the Jews.
BTW, the US accepted very few Jewish refugees during this period, other than scientists and others that would be useful to us. Couldn’t have a massive influx upsetting racial balances in a country of 100M+, but apparently the same number of refugees going into a country of <1M shouldn’t have upset them.