You didn't read the quote, did you? Pay attention to this bit: According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense.That's Einstein in 1920, explaining that spacetime must have some real physical qualities (exactly as Xelios pointed out).
