Yes, but the British knew that the zionists wanted to set up a Jewish nation. The zionists were well-known for their desire to set up their own state.
So, there are 2 possibilities:
1. The British were very naive.
2. The British indirectly supported a Jewish state in Palestine without saying it out loud in the Balfour Declaration.
Probably, it was the 2nd one. The British chose for the safe way, but they probably knew that the Zionists would set up their own state.
Provided it did not prejudice the indigenous, non-Jewish population.
True enough.
Then again, that was an asinine provision.
All 'outsider' proposals to create a Jewish State in Old Palestine seem to have included such a provision.
It was tantamount to saying...
"
You may have your own State embedded within the lands of Old Palestine, but only if you can convince the tribal folk and townsfolk of the region - who are members of a competing religion which has held yours in thrall in second class status for centuries - and which has been in a sporadic shooting war with you for the past 3-4 decades - to let you become the new masters of the land, rather than them. We all know this is never going to happen but it lets us pretend to have sympathy for your aspirations while winking amongst ourselves and chuckling behind your back while you're not looking."
Realizing this truth, the Jews said "Fuck that!", screwed-up their courage, and fought for a home of their own, and rationalized it by cherry-picking the best parts out of those proposals.
States are rarely created by man-wussies who prostrate themselves before their enemies and ask 'pretty-please."
States are usually created by men with balls who fight for a home, and win.