How is Israel a pipe dream? It's been in existence since 1948, has a successful democracy, is a staunch ally and has single-handedly beaten every nation which has attacked its borders. It's the one island of respite from an arab sea of intolerance in the middle east. So seems to me the "pipedream" is a reality, not to mention the fact that it is in our national interest to have a reliable ally in the area. What you also0 seem to forget is that there would have been no need to support the "Zionist pipedream" as you call it had not Europe and the U.S. been opposed to allowing Jewish refugees onto their own shores.
Your arguments about British imperialism resulting in them giving land that they perhaps shouldn't may be accurate. But the British did that with lots of different countries and the fact that you only object in the case of Israel speaks volumes.
And so you know, to me, the survival of the one measely little Jewish State in the sea of how many Arab nations, really isn't up for debate. But that's my own personal bias.
Sometimes it's just right to do the right thing.