“The British didn’t write it due to any love of Jews”
Actually, the two most important British leaders at the time — PM David Lloyd-George and FM Arthur Balfour — both fancied themselves as philo-Semites. Lloyd-George in particular seems to have enjoyed thinking of himself as the man who would return Jews to the Holy Land. Winston Churchill also fancied himself a philo-Semite but he had little input into anything at that time.
Also worth noting was that the French PM at the time, Georges Clemenceau, also liked Jews — he was the newspaper publisher who published Emile Zola’s famous “J’Accuse” defense of Dreyfus. He liked the idea of a Jewish homeland in Palestine, too.