We humans started developing the astral body only in the fourth race. Is it correct to say that until then the mineral, vegetable and animal kingdom received no affection/love from us and so they had no scope to evolve? In other words, is it right to say that the mineral/vegetable/animal kingdom were in dormant states until humans developed feelings (astral bodies) which happened only in the fourth race?
No, it is not correct to presume that humans did not start developing astral bodies until the fourth race. The development had started ever since the first race. However, as explained in the book, a special impetus for the development of the astral body for majority of mankind happened only in the fourth race.
It is not correct to say that until the astral body was fully developed the mineral, vegetable and animal kingdoms did not receive affection and love from us and therefore had no scope to evolve. However, with greater love and affection, their evolution has been somewhat hastened. This hastening will continue to happen in later races and in an accelerated manner. So, the mineral, vegetable and animal kingdoms were not (and never) in a dormant state. Their evolution is totally independent of the development of humans. However, presence of more evolved higher kingdoms of life always help in the evolution of lower kingdoms of life. The fourth race, is just a stage of evolution of the human race.